$1300, that is a smoking deal, I paid just a hair more for mine and it was in much worse condition than that, you can see my pics a few posts, Only 15% finish remaining.
My gun is an AC43 and it shows no external EP markings. My mag was missing so no help there, I have the french repro which is patterned on a DUV mag.
The locking lugs on mine appear to be EP'd, but that is all that comes to mind.
I am not sure they saw that much hard use. From everything I read the front line troops didnt care for them much and they went to second line troops. Certainly were fired in anger on the Eastern front though. I have oftern wondered of the G41's in the US, how they came to be captured by the Americans. My 2 thoughts are from units transfered from the eastern front prior to or just after the Normandy invasion, or units that fled the russians as the war was winding down looking for an American to surrender to. Sorry I think of these things.
I actually dont think mine feels much heavier than my G43 with a ZF4 scope. Defineatly balanced differently though.