Realistic price on the Browning Model 52B sporter in 90% cond. is anywere from $900-1100, unfortunately the Winchester ones are more sought after, the only differrence in the Browning I had to my Winchester was how the barrel was secured to the stock basically? Wood seemed to be better on the Winchesters.
I bought my Win 52B sporter in the early 1990's, and it a one hole 25 yard shooter with CCI ST VEL, still have the first one hole group I ever got! Started me into accurate 22 LR's, a fever that never is satisfied!
You have a gem, Leopold makes bases and rings for them, also Talley has a nice set available. If it were mine I would shoot it, not sell it, but good luck!
Cheers Dale Z!