Well the Model 17 is a great revolver and the 4 inch barrel is extermely hard to find asthe 6 inch barrel was the standard barrel length. In fact I have never handled a 4 inch Model 17 and I think they only started making them in 1990 with the full barrel under lug.
So the question is do you want an older 4 inch blued S&W model 17 then you should actually look for a Model 17-6 with a 4 inch barrel. It would be easier to find a Model 18 which comes in 4 inch barrel and they are great shooters. Or if you want new get a 617 with 4 inch barrel.
Model 17-1 22LR with 6 inch Barrel
Model 18-4 22LR with 4 inch barrel
Model 617 no dash 22LR with 4 inch barrel