Thanks for the reply. It is at least a starting point for research! My grandpa had this thing for 20+ years. I figured I should check on what it is since he also had an 1855 pattern Richmond arsenal Confederate bayonet. 

Someone has already replied, but I would like to add that this looks like Ontario's commercial offering, despite the US stamp. I have one just like it that I bought direct from Ontario some years back. There is a subtle change in stampings between this commercial line and the post-Vietnam military line. Notice how the E in knife is almost at the edge of the blade. Not so on the military examples, which I've posted below

do you have any references for the markings 

hello, It is unusually crude.  I have not seen one like this.  The British exported hundreds of thousands of Enfields.  I know a huge cache was discovered in Nepal some years ago.  These rifles are the 'commonly' seen ones on the different gun platforms.  My hunch is this bayonet was made somewhere like Pakistan, India, Nepal, Afghanistan, etc. as a replacement bayonet.  I was in Afghanistan as late as 2010 and later.  By the time I got there, the 1853 Enfields sold at the market were fake copies.  But I am aware the early guys did get to buy original Enfields.  I would guess the real one disappeared around 2005 or 2006.  But that is just an educated guess of me asking around. Sorry if this is no help. cheers!

wow, incredible score! congratulations.

Saving private ryan?

Unissued?  Someone poked holes in it. 

"The Longest Day"  Ham and Jam! Ham and Jam! Up the Ox and Bucks!   Episode 2 of "Band of Brothers" will need to be watched as well.   Allan

What's the movie of choice for tomorrow?

A few knuckles in my collection. No more are being made by EDMF.