SuitbertW
2411
You'd find the ser. number inside case back...
Hi Gio,
ref. 2591 and 60ties is matching. The ser. number and movement ser. number you'll find inside case back and on the movement mainplate.
For a rough idea about value, I'd recommend to check auction houses archives (antiquorum.com, sotheby's.....) - type in "2591" and "Patek" for example and you hopefully get some usefull information.
Hope this helps a bit
Best regards
Suitbert