A lot of these were Belgian made. Does it have Belgian proofs? Consider that Webley RIC's with antique status go for about $1300-$1600 in that condition. If it's slightly worse condition wise, but good mechanically with a good bore, I'd guess about $400-500 less than that. If it doesn't have antique status (and most of the RIC copies with the side lever safety's don't qualify) then knock off another $300-400. These are all just very random guess's, since without the actual gun in front of me I couldn't give an accurate assessment. Good luck.