It’s different to the online pics you see because it has been redialled. And not very well.
It is a 2828, follow the link above posted by Christos for details. Your date estimate is about right, I’d put it at 1959 based on the serial number. It’s a mid size model so small even for an era where watches were smaller, the full size fat lug Seamasters were 35mm wide. It’s not massively desirable unfortunately and I concur with the estimate above, I guess it might make $200 if running to an unsuspecting buyer. If you are looking to sell it I suggest eBay, it won’t get much interest here.