This gun as everyone else has stated, is the same gun as a Detective Special of the same era.
I bought a 1963 model in 2007 for $300.00 it was at least 98%
and I enjoy shooting it occasionally.
Another way to look at it, it is a fixed sight variation of a Diamondback...
Now those sell for $700.00 on up on the auction sights.
I think anything under $500.00 is a good price for the gun you described.
But remember , it will not sell easily like a Python or Diamondback will.
But the internals and action are very similar.