Gerber MK-II:
Just as the Fairbairn Sykes is the Iconic knife of WW-II, the Gerber MK-II filled that role for the American soldier in Vietnam. I recently discovered that I was wrong about the original designer. The MK-II was designed by retired Army Captain Bud Holzman, not Al Mar. The MK-II were a much stouter knife than the F~S and employed better ergonomics in the handle.
The photo below gives you an idea of the wide range of handle styles and finishes that were used during the time the MK-II was first produced. From left to right: a 1978 black matt handle, grey cat's tongue, black glossy, grey smooth handle, and a 1968 with less aggressive cat's tongue finish.  
An array of blades showing variety of profiles and differenes between serrations and two non-serrated blades. All of them are wasp waisted to one extent or another. Interesting, perhaps, is that the smallest blade in the middle is also the earliest one from 1968. Several of them are canted blades including the one on the left which is from 1978. The "canted" blade has a five degree bend at the guard which was intended to make the knife lie closer to the owners body, to prevent the handle from snagging on jungle undergrowth, clothing, or gear.
These two knives have their handles held parallel. The top knife has a canted blade. The lower one has a straight blade, for you to compare the two of them. Canted blades are rarer and therefore more desirable.
Sheaths came in a variety of shapes and colors. Some were fitted with a pocket for a stone or steel, others were plain. You can see there are black, dark brown, and a natural tan colored exmples. They all have the metal GI style belt hanger except the one on the far right which is likely a replacement sheath. The knife with the glossy black handle came in this sheath. It is missing one branch of its guard and actually fits pouch-like down into the sheath.
Randall Made Knives:
Bo Randall (a true Southern Gentleman) of Orando FL. built a better mousetrap when it came to double-edged fighting daggers. Hand-forged and hand-ground blades were fitted with neatly shaped and soldered brass guards and leather washer handles, they are topped with stout aluminum butt caps to balance the knife. This particular knife is a Model 2 with eight inch blade dating to the Vietnam War era. The handle shape is still referred to as the "commando" handle.
This Vietnam era Model 2 is in mint condition, pretty well eliminating any chance that it was ever carried in combat. Many times stronger than a Gerber or an F~S, it is an excellent fighting knife.
 
Arkansas Toothpick:
Randall also offers a "Toothpick" design which harkens back to the Old West and Gold Rush Days. The toothpick comes in several different lengths from boot knife size to bowie size and with many handle options.
There is no finer fighting knife in the world than a Randall Made knife. They have been serving American fighting men since WW-II providing only the best in materials, rugged construction, and superb designs. The handmade blades are available in a carbon steel or stainless. Note the "S" on the top blade indicating it is a stainless steel.
If you are very patient you can custom order exactly what you want but expect to wait about 3 years for delivery. The best bet is to buy from one of many dealers who suck up all of the production, causing the long lead times. Handles way be had in either the standard leather washer with aluminum butt cap, stag, or micarta. It is hard to imagine any fighting knife that would serve its owner better than this 8 inch bladed model 2.
Randall is also justifiably famous for several large Bowies and bowie style fighting knives, notably its Model 1 and Model 14 (both were very popular during the vietnam war). They are also famous for their Model 17 "Astro" survival type knife which was carried into outer-space by numerous astronauts.
Here is an array of the famous Gerber MK-II fighting knives. They were, without a doubt, among the more popular knives to own and carry during the Vietnam war. The handle is extremely ergonomic, the blades were delivered hair-shaving sharp, and they came in a well designed and high quality sheath. Note the knife on the far right has had one branch of the guard shorn to provide the owner with a thumb ramp. This was not uncommon. I have in fact seen others with both arms removed to make the dagger even more low profile. The handles were tough, cast aluminum with an integral guard. The Gerber MK-II of that era was one of the finest fighting knives ever made. The new ones seem to lack that same gracefulness and elegance. During photographing these kinves I discovered that the blade of the 1968 knife is strongly magnetic? I am not sure how that might have happened or when.
As I mentioned once or twice before, I have a weak spot for old Tomcats like this knife. Pristine knives to me are generally boring knives.