Could be a tough find. Best bet might be to buy a ratty 1620 and swap movements. Like this one, described as having a "pie pan" face: https://www.ebay.com/itm/VINTAGE-SP...616877?hash=item2623b1df6d:g:nd4AAOSw065dSmsZPurchases made through these links may earn this site a commission from the eBay Partner Network