QUOTE(markb @ Feb 6 2012, 01:11 PM)
If you bought NOS, send it back & get a replacement.
BTW - these are still available NEW from Porsche & the other usual suspects.....err.....suppliers - both L & R mirrors, including the very slightly convex pass. side one if you're wanting to add that margin of safety to your 74 project (I got both sides new for my 73 2L resto & they were perfect).
If you bought it from one of them, call them & insist on a proper replacement & they should comply, but if a private seller selling NOS it may be a bit harder.
If no satisfaction from seller, try credit card complaint/purchase coverage route, or bite the bullet & buy 1 or both new ones from Porsche & just resell this one with proper disclosures. It's not worth the hassle to try to replace the part (a real PITA) to hope to get to 100%.