Seamaster 166.011 “Jumbo”(?)

I purchased the oddly double-stamped 166.011 I posted about recently out of curiosity and an apparent inability to understand the difference between putting an auction on my watch list and actually making a bid on it.

After putting it on a BOR bracelet and swanning around with it for a couple of days, I rescind my earlier opinion about its apparent size. The extra 2.5 mm over the 166.010-type Seamaster models I’m used to, plus the plumper styling, feels like the difference between a Chevy Corvette and Ford Gran Torino.

The state of the stem, which I overlooked even though it was readily apparent in the auction photos, seems suboptimal. I made a halfhearted attempt to remove it, but it didn’t budge. Very probably relatedly, the center of the crystal fogged up a bit on a hot day, to the point that water droplets were visible inside the crystal. I’m sure this is a “get thee to a watchmaker” situation, but I’d be grateful for any insight anyone has.

I missed your initial post on this, but I think it's a great watch. Really nice size IMO. I have seen stamps like that before, although I don't recall if I've seen it on an Omega or not, but it doesn't bother me. I assume there is some rust on the stem, and yes that does suggest that moisture is entering, but I guess you already knew that. It's such a nice watch, I would hate to see it suffer any water damage.

I am really liking it. The design, especially that crown, is just slightly a throwback to the fifties, compared to the sleeker 166.010/168.024. The lumeless, unadorned dial is bracingly stark. I wondered if I'd prefer one with onyx inserts on the indices, and maybe I would, but this one has really grown on me.
It has been downright steamy in Tokyo over the past few days and I've had to take it off while I'm working because of how fogged up it gets, so I'll make the hike out to "my" watchmaker next week for a consultation.