Check with GENE BUNCE in Mass who advertises in the national magazines.
I purchased a chrome frame for my 68C from him a couple of years ago and it still looks great.
A&L sells them for the open cars but they are made by the same vendor that everyone else sells. Come plain metal or plated I believe. I put one on my phaeton and it looks great. Very well made and everything fits just like the original. The open car reproduction windshield frames are a good buy.
Didn't even think to ask. Is there something wrong with your frame other than bad chrome? If not, probably easiest, cheapest way would be to just get it replated. Comes apart pretty easy into two pieces.
Not that I know of. The snaps along the top front were not originally screwed in so if those snaps are screwed in with a slot head screw driver, might be a sign. Plating isn't cheap but probably still cost less than buying a new one. Who ever does the plating might be able to weld up any pin size holes for you as well.