I agree with Coryjoe about signing and dating your work. It is a must.
I think that 50 years ago or more, the idea of changing something on an original horn was mostly not given much thought. Many original guns were scrapped for parts to make new ones if they weren't in shootable condition. Values, collectibility, historical value, etc. are things that have changed a lot in the last century. The idea of making a quick buck by changing how old something appears to be is certainly not new. Just kind of new to our particular hobby. It's kind of irritating.
Steve