Please Help

[Meridius]

Now the second luger. This one is a blank chamber DWM that I bought as a shooter. The top half is matching to itself while the bottom frame assembly matches itself. On top of the barrel (not the receiver) the number 1928 is stamped in a small font. Is this a rework from the 20's or is it a recently assembled parts gun? It is reblued but I'm not sure when or what kind of bluing it is. What is this thing??