Ramrod is correct that USPFA guns are always Uberti parts. USFA’s are the parts mix on earlier guns.
Condition is always the most deciding factor on value. As described at NIb condition -100 % complete then $850 is a very good price. Even though the USPFA is Uberti Parts, they normally come in the blackpowder framed, bullseye ejector, wooden grips , with excellent to outstanding case hardened colors and blued finish, which is all a very desirable configuration and be worth at least twice that if it were a USFA and apparently $2500 to $3K (latest crazy gunbroker prices) if it were a Colt SAA in that configuration. So I’d buy it and you’ll likely be very happy with it.
FYI, an early USPFA gun will be a white box (black sleeve if it’s still with the box) and USPFA inner labels. Serial stamped on on end.
Later models had a black lift top box , USPFA labels, and very latest USPFA’s had a black hinged lid box USPFA labels.
Manuals and hang tags pretty much the same through the course of USPFA guns.