Someone asked a question on a different web site about all the differences/similarities between the many different models of  Ka-Bar knives.  Here, in a nutshell, is a  beginner's guide:

First, there is the basic (and original) Ka-Bar knife that has USMC stamped on the blade.  It has a 7" blade and is 11 7/8" inches in overall length.  It has a stacked-leather handle that you'd swear was wooden.  This  is model  #1217.  The many variation models start to branch out with "US Army, " US Navy," and "USCC" stamped on the blades.  They are all the exact same knife as the USMC model, except each has a different stamp.  And then there are many commemorative knives:  VE/VJ Day, Vietnam, Iraqi Freedom, etc.  These each have their own model numbers as well, but again, are the same basic knife.

Secondly, there have been different blade types added to the product line.  Some of the main ones include the regular straight edge, the partially serrated edge and the tanto (rhymes with "can't hoe") blades.  There are others, in both fixed blades and folders, but these account for a large chunk of the product line.

Next, many of the above-mentioned knives have been manufactured with a newer handle material called Kraton-G.  This is basically a rubberized handle.  It's very comfortable in the hand and is very non-slip.  Once again, the knives that have these types of handles all have their own model numbers. 

And finally, most of the above-mentioned blades are offered in a shorter knife.  These shorter knives have a 5 1/4" blade and are 9 1/4" inches in overall length.  Most of these shorter knives come in all of the above configurations, except the commemorative models.  These short knives can be found with a regular straight edge blade, a partially serrated blade or a tanto blade.  And most of these  can come with either a stacked-leather handle or a Kraton-G handle.

The last thing to cover in this guide is the sheath.  Almost all of the above-mentioned knives can be purchased with a leather sheath.  They can come in black or tan.  Many of them can also come with Kydex sheaths.  The same knife will have two different model numbers if it is available with both a leather and Kydex sheath.  If a particular knife doesn't come with a Kydex sheath, you can always order one for either the long or short blade.  Most knife people feel that  Kydex sheaths are better because they don't hold moisture like a leather sheath will, therefore allowing less of a chance of  premature rusting of the blade (now be honest, how many people only take out their knives once every 2-3 years?!?).

So how many different model configurations are there?  Take a full-size knife, choose between a straight, serrated or tanto blade, a stacked-leather or Kraton-G handle and a black or tan leather or Kydex sheath.  Throw in the short blade knives, not to mention the commemorative knives, Warthog, Bowies and Camp/Machete//Kukri knives, and you do the math!  That's a bunch of knives.  And then you have the folders and new technology knives, etc...  Maybe I'll cover those in a different guide.