You can import these from the USA (so USA $ + $250) to give you a basic idea.
Gunbroker.com lists a few, but not many with 6.5" barrel. The one round butt example I found was offered at $1600 "buy it now", $1350 base price (so still $1600 if you got it at the base price and imported it). That one was also round butt, which is a bit more unusual.
A square butt "classic" model with 12 days left was already at $900 / 10 bids, so I'm thinking if you sell this for less than $1200 you've left a bunch of money on the table.
I'm a fan of the 625 (.45) and 547 and 940 in 9mm Smith revolvers. I found the 610 a bit too snappy in 10mm but didn't get to try it with .40, which might be OK. The Smith revolvers are wonderfully accurate to start with, and seem even more so in the semi-auto calibers.
You have a highly desireable and valuable revolver (or your dad does). A fair price if he's selling it to you would be a hug and a sincere thank you, I would think. If he needs cash, somewhere between $800 - $1200. For a stranger, $1200++. Don't let him consign it.
At 3000 rounds it's about broken in. If you stick to .40, you'll go broke buying ammo before you wear it out. Shooting 10mm, you would certainly go broke buying ammo.
