I couldn't find it on that site, but here's another Baker reproduction from a U.S. importer:
Here's MVT's faq's page:
Just like with most any new gun, they can lose value immediately after being purchased and used. And I think that if more money is invested into the gun to customize it then there's the potential that for even greater depreciation. It may depend on whether one knows of reenacting group members or BP club members who might be more interested in buying that particular model. Otherwise it could be a hard item to sell and some depreciation should be expected.
So personally speaking I wouldn't modify it unless I were planning on keeping it for a long while.