Legit serial number range for 1939 Mauser 42 Code Luger?

[G.T.]

I'm just speculating right now, but the whole serial range dilemma can never be nailed down as absolute as there was almost always overlap between variations and their specific markings, plus "using up of old parts" has always been an undetermined variable as well?
But, if everything else on the gun was correct for a late variation 1939/42 then I would think it was just some overlap into the "no letter" range after the end of the "z" suffix? Start comparing font and strike size on the gun with other examples, it should become readily apparent if something is amiss? Good luck, might be your first major lesson in Luger collecting. Believe me, everyone here has been on the same cliff you currently occupy... Pictures would be great... otherwise, you've heard about all there is for now?.. best, til....lat'r....GT...