It's an interesting thought and I certainly wouldn't want to shoot you down over the idea. Those 'in the know' would recognise an Anniversary providing it hasn't been mucked about with as regards to the vehicles identity. Yes, some have different wheels, different exhausts, suspension that is too low etc, etc and i'd think it may appeal to the owners of those vehicles.
Do bear in mind that original cars are increasingly being broken up and I think the demand for the badge would be quite low. Me personally, I wouldn't want one because I like to try and keep it original looking and secondly my car is red! Identifying the red badges is hard enough as it is!
However, perhaps a window sticker might show more demand? But there will still be a limited market.