anybody ever seen one of these before?

[coltguy]

Hey guys,
been into guns for 30 years plus and this just walked into my gun store today, and i have to say i've never seen anything like this before.

there is no serial number on the bottom like normal, and no markings anywhere except a DWM top strap, and a BARELY visible made in german stamp on the grip frame in front. It does not have a stock lug, the magazine is fixed and cannot be removed which is why the button is on the right to depress the mag follower so you can load it from the top with the toggle locked open. The straw coloring looks too new, the gun shows no marks anywhere except the dwm link and the made in germany on the grip frame. and it is in .45 ACP or will at least chamber a .45ACP.
barrel has two plugs in it - maybe used to be drilled and tapped?
There is no

I thought it might be a LUGERMAN gun or maybe one of the waffen werle guns but i see no makers marks and ive not seen a fixed mag variant.

Anybody ever seen anything like this before?

Thanks
Mike