I have same as OP - Serial number also ends with "RN173" - 1979. Fixed chokes - "*" on top barrel; "**" on lower barrel at chamber end on left side. Easy enough for OP to check there to confirm if originally had fixed chokes. A mid rib sight was installed on mine when I received it - I do not know if that is original or not. Paid $1,430 delivered to me in Dec. 2013 (I checked, not from 3macs1 above!!)
Bought mine about the same time, 1295$ delivered to my door. There seemed to be deals all over the place then, dealers seemed to be dumping them