The mixing of parts in rifles (with a dozen possible variations between individual rifles) as a particular model is changed is not unknown - and I can only imagine German weapon manufacturing and assembly plants in 1945. There are probably a score of “unique K98 models.”
With the K98’s cousin, the venerable Springfield 1903, Remington took over production originally making them with milled parts and the original sights as always. As WW2 progressed (late ‘42/early ‘43’ish?) in a effort to speed production the (America’s Krieg model?) 1903A3 was introduced with stamped parts and the now standard rear peep sight.
The 1903A3 didn’t just appear overnight and new production stamped parts started being used in the still ongoing 1903 production (and during repairs and refurbs) sometimes being called (incorrectly I was told) the “1903 Modified.” A 1903 Modified could have just one stamped part or several different ones. And this even applied to stocks leading to the notorious (definitely Krieg to me) “Recoil Pin Model” with nails (essentially) instead of reinforcing bolts leading to further variations as production and repairs progressed.
I find the analogy between the K98 and 03 interesting. I further wonder how many “humped” K98’s were actually factory made as milled/stamped/whatever parts were being changed over or used because of supply issues. How many factory made K98’s have been “fixed” by post war collectors?
And as a disclaimer the above is by memory after one cup of coffee in the pre-dawn darkness.