Should be a very interesting thread and very useful thanks . When I started collecting almost two decades back and getting my authority to buy live rifles. I went to virtually all the main gun fairs , auctions , trawling gun traders websites (still do). My first ever gun was always going to be a WW2 K98. When looking, I remember hardly ever seeing 100% German matching rifles, it was the norm to see a bolt mismatch. Maybe I was the most unlucky person ever back then ?
These days I now struggle to find stamped serialized ww1 / ww2 guns that don't match. Indeed many I have had in my collection including now I am a little ??? , however the rifles are still nice, and the next bloke would of have it if I didn't. This is why I have generally steered over to some antique "oddball" guns that are less likely to be messed with.
Of course, there are still many many gems out there to be had, of which we will find.
Stay safe collectors !