Were there any stampings on the bayonet, or any components? Or is it staked?
I ask because that is the nicest looking M59 bayonet I have ever seen. They usually are very dark, and kind of blotchy....almost like you used them to stir up a campfire.
I just checked mine, and it is staked, but I didn't see any stampings or anything....not that I think they do them...I was just curious, your camera sees better than my eyes.
I did notice though, the bluing on the handle doesn't quite match the plum-like color the rest of the gun has...at least in current lighting. So if you notice that, I wouldn't necessarily think it was replaced....but it is kind of unusual for that to be so, well...silver.
Very sweet gun though...and not so easy to stumble across.
I dunno about the serial, but those closeups make it look as if they used a stencil guide for an electro pencil, rather than stamping. I will have to see in better lighting if mine appears like that too. Perhaps whoever did it just oopsied and covered it as best they could?