Gotcha, I see what you are saying. I might have to borrow a friends Argentina and try to look at them side by side and get measurements. Both sides of the frame have been ground down a lot. Almost like they put it on a huge belt sander or something and removed the metal. The frame has had a lot of metal removed. I can tell as the mag release protrudes out on each side much further than it should. The receiver is not cast and does appear to be forged, so you very well might be right. I am not ever going to make claims of originality on this one, or really any Experimental to be honest. I just don't know enough. I do believe I see the Army markings but maybe I'm mistaken. It wouldn't be the first time.