The habit of using up parts etc is exactly what makes me hesitant about this. If you come across a gun with a mix of older and newer features, is it evidence of what the factory were doing in the 50s, or is it someones shed tinkering last year? And then there is guns returned to factory that were fitted with later parts.
I guess it doesn’t matter much for guns where there are thousands still in circulation but I feel it’s a bit iffy otherwise