They are certainly rarer then the standard model with the regular sight package. I had a 586 with 8 3/8 inch barrel with the Silhouette sight package and sold it and I wish I hadn't. Not sure of the value of these revolvers because to the right buyer they are worth a lot. The buyers tend to be hunters that can set 3 different zero points with the sights or competition shooters.

Mint shape I would guess $600 to $650