PAM 390 question

Hi all, having some doubts and was hoping I could get some help here.

I saw a 390 for sale at my local jeweler. Lightly used in great condition, triple boxes with complete papers. Looks good there.

I own a 164 and a 88, and when I picked up the 390, it felt slightly lighter in comparison.

Also, winding the 390 was more "clicky" and with less resistance compared to my other pams. Have never had a OP I or OP X pam so I was wondering if this is normal?

Paranoid, especially with the easy availability of high end reps nowadays. Saw a rep 390 and 111 the other day and they blew me away! Not as easy to discern as the crappy reps just a few years back. Any advice apart from the usual 'buy the seller' line? Has anyone heard of a rep which comes w apparently legit looking papers and full set?

Thanks in advance guys.