Based upon what I paid for my original Porsche mirrors for L & R (real convex factory right), the $270 would be about it's price today, & AFAIK they're still available from Porsche - so I'd suggest that if you're willing to pay $270 each, just go to the Porsche one.
Both Suncoast Porsche & Sunset Porsche have online parts sites which typically give 10-25%+ off list price, so you should be able to get them both in correct part nos.
Also IIRC, on the originals - it's only the bases & arms which are chromed, while the mirror housings are polished SS or aluminum.
Even my 44 year old originals from it's Aug. 1972 build didn't pit on the housings, while the bases & arms did - ergo why I got new matching condition L & R for my resto, since I wanted to add the passenger mirror for safety.
BTW - if you don't want to go to the expense on new originals &/or the R-convex originals are now NLA - you can still use a driver one & flip it for P-side use. It will be flat, but in fact the factory P-side was a very low 10-15% magnification from the convex, that it was very hard for me to tell that they were different. So you're not losing much on visibility with the driver one on the right.
Tom
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