i bought a 4 inch barrel police service six for $150 recently, the bluing is about 90% but only had cheap rubber grips on it. i wished i had started looking for these guns before now.
I bought mine (2 3/4" SS Security Six) new back in the 70`s. If memory serves it was a hair under $300. I do know I paid $335 for a new Ruger # 1B at the same time.