I purchased a project 1917 .32 pistol yesterday and it came with what is seems to be a 1915 .380 magazine - it has the slide hold open tab on the follower. I do not know if this is an original or a repro. Are there distinct features that might tell me which it is? All the 3K .380 mags I see online do not have the tab on the follower and the round count slots are on the right side of the mags. Mine has the hold open tab and 4 round count slots on the left hand side of the mag. It also has upper and lower catch holes and is not stamped "380 cal", but accepts .380 rounds easily and has a slightly wider profile than my .32 mags. The rib on the back of the mag is identical to ribs on my .32 mags that I know are original and not full of the round spot welds I see on repros. Any guidance would be most appreciated.