thanks Ken, the only examples I have ever seen with a ground frame such as you describe were poor attempts by amateurs to "create" a new pistol from a stolen one by eliminating or changing the number on the front of the grip frame and replacing the upper assembly with one made from parts guns.
This usually causes a noticable gap between the upper assembly and the lower frame such as you have described.
This photo shows the hard line that is usually created when the front of the frame is filed off to allow the new number to be stamped in...
IMHO this particular gun was renumbered to be serial number 11.
Notice in the inset photo how this causes the upper receiver to stick out past the grip frame when assembled. Walk the other way when you see these signs... be very afraid. I would personally never buy a gun with the combination of these conditions.
Here is another example of a possible defacement of the grip frame serial number... notice the hard line from the grind operation, the protruding upper receiver when assembled, and a lightly stamped serial number...
IMHO this second photo also shows that the suffix letter was stamped before the grind operation, and after the grip frame was ground, the letter 'm' was "touched up" to be the same depth even though it passes over the irregular surface of the grind mark.
In your case, your receiver sticking out appears to be the result of the mismatched takedown lever.
Lucky you. [img]smile.gif[/img]