[alanint]

With no Mauser hump to muddle things, the lower frame would indeed match the balance of the pistol. The font looks consistent throughout the pistol, (with the barrel being a close approximation).
My guess would be an Alphabet Commercial, rebarrelled to 9mm at a depot for Weimar government service. As such, the pistol is in a sense "correct", although many purist collectors would rate the gun a bit lower than an untouched, factory original pistol.

Still, I find guns with a decipherable history of great interest.