Newcomer, I own a vintage Pie Pan and love it. You need to be wary however when purchasing vintage watches on Ebay as many so-called frankenwatches exist. I suggest that you post the link to the watch on the Omega forum on Watchuseek - it is a very friendly sub-forum, and there are a few people there who are good at spotting frankenwatches.
I am contemplating whether to pick up IWC Big Ingenieur.. Jeweler I frequent had one in such attractive price ($6K while it's retail is little over $12K) but having no box & paper deterred me from jumping on it at the time and now I can't get this watch off my head... Another thing is, it was limited edition of 200 that came free with Mercedes SL 65 and there is SL 65 engraved on the side of watch case while I don't own SL 65... This model has IWC manufactured movement and I am not sure how reliable they are since I never owned IWC and how hard it will be to acquire parts if needs to be repaired.