Hello! I'm looking to buy this watch. It's a watch from circa 1949, with Girard-Perregaux 82 ( Peseux 220) movement but with extra detailing and 17 jewels not the fifteen as standard Width with crown 25.1 mm I'm inclined , from my research, to say that this watch is authentic, and the seller has good reviews. I'm just a bit hesitant because I know that the "antimagnetic" on the dial in a vintage omega is a no no. I don't know enough about GP and didn't find enough information to say with absolute certain that this is common in GP watches. If you could be so kind to help I would be very grateful!