I have tracks on both models, maybe a bit out of date. Here ya go:

Smith & Wesson 617 Plus 6 in barrel Revolver in .22 LR. Blue Book of Gun Values (38th Edition) indicates between $615 in 95% condition and $735 in 100% condition for this gun. I have 92 recorded prices for this model gun from $350 to $1300 over a period of 14 Yrs 8 Mos ending May 2, 2018. The average price as of that date was $592. No refurbs, no refinishes, regular sights. All represented as 95% or better. No distinction for import location or engineering revision, if any, no special editions, no distinctions for box, papers, tools. Current or last MSRP is $829. The last 10 prices I have for this model since 4/30/2017 range from $545 to $1300 averaging $865.

Smith & Wesson 66, 2-1/2 inch barrel. Revolver in .357 Mag. Blue Book of Gun Values (38th Edition) indicates between $578 in 95% condition and $(no value given) in 100% condition for this gun. I have 111 recorded prices for this model gun from $423 to $1095 over a period of 6 Yrs 2 Mos ending January 7, 2018. The average price as of that date was $710. No refurbs, no refinishes, regular sights. All represented as 95% or better. No distinction for import location or engineering revision, if any, no special editions, no distinctions for box, papers, tools. Current or last MSRP is $614. The last 10 prices I have for this model since 3/7/2017 range from $575 to $925 averaging $782.

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Bob