Condition is everything, as is the actual configuration. "Late `50's, early `60's" is too vague for my tastes. Is it a 1955-1962 "flat-top" or is it a model with "ears" around the rear sight (1962-1973)? Is it original? If it's a flat-top, it needs to be in very good condition with at least the original grip frame if not also the original grips, which most Rugerphiles like me put at least a $100-$150 premium on. If it's an "eared" model, it's way too much money regardless of condition. The problem is that many dealers price "eared" models like flat-tops and some even advertise them as flat-tops. Either out of ignorance, or hoping to separate an ignorant buyer from more money than it's worth.
If it has been converted and does not include the original parts, it's WAAAAAAY overpriced.