If you have the option to examine the watch in-hand, by all means, exercise it. Until and unless you can physically verify the watch is, in fact, fully working, it's a potential disappointment. Bear in mind, the box is incomplete, and there are visible chips on the lower edge of the glass (plus side...looks like a full-length bracelet). For the price ($294), this is an OK deal, but not a bargain. It's a decent-looking "wearer", but if you're looking for a serious collector's-condition piece, this isn't it.
BTW, there is no such thing as a "408" P4 module. There is a 401 (magnet-set), 402 (Auto-Set), 403 (DOW display), and 406 (24HR display). If this is represented as being a 24HR module, look at the Date display (if there's an AM/PM dot, it isn't a 406 module; and, all 406s are Auto-Set, so you can run through the hours and see if it goes to 13 after 12, instead of back to 1). I notice there's no pic of the Date working, so be sure to check that.
Finally, this is a Model 5201-2 Executive; 4000 is the module series.