There was talk once of a 'Wedge Works' of sorts being set up at St. Ives but I don't think that has happened as yet.

I think the stamping would have to be done at time of purchase, if there was a WW here in the UK, I'm not sure they would take a wedge back to do stamping and a new / different finish or a restoration isn't something that is offered by WW in the US so I doubt that would be an option here.

Changing the finish might be a bit difficult, but if you don't use the Tour Chrome you can do the stamping yourself. If you get a set of stamps from a local machine supply house, the material is soft enough that stamping is pretty easy.