Yes, adding the bracelet to a 48 makes it a 50 apparently. I wonder how much it would cost to buy the bracelet separately? I saw a very nice white faced version the other week, pretty different for a Panerai. My ideal Panerai is the 44mm power reserve with centre seconds, PAM27.
A 40mm 2007 Pam50 apparently, from http://www.lunaroyster.com/watches/2007-panerai-luminor-pam050-40mm-on-bracelet-box-papers-pam-50