Good information so far. I did not know that blued hammers exist on the DS. It was a very bright high polish blue that looked just like the rest of the gun.
Full blue hammers are a sure sign of refinish, or at the very least a refinished hammer, but who refinishes just a hammer?
Colt's triggers were always finished to match the gun. So a nickel gun would have nickel trigger, blue with blue, and the entire trigger would be finished that way.
The same is true for the hammers. They matched the finish. However, with the hammers, they would polish the sides to 'in the white'. So only the edges and spur and some areas within the frame retained blue. With a nickel hammer, it was full plated. Colt really didn't do the cch of triggers and hammers until they started the sintered steel parts, such as the Trooper MKIII, but even then the triggers were still finished in blue or whatever and weren't cch. When stainless came out, the triggers and hammers were stainless.
So a full blued hammer tells me refinished by someone who doesn't know the details of Colts, unless I can verify the rest of the gun, but usually it is a no brainer from all the ones I have seen. Colt used better steels and didn't need to cch.
As for price, a refinished DS would have to be $300 or less for me to buy it. Everyone is different. I passed on a Cobra for $350 not long ago, didn't want a '50s alloy frame. I have seen nice original Detectives selling for $400 or less and were maybe 85% condition on GB. I would go with that before a refinish at $599. Of course, I can fix and repair my own revolvers, so I have an upper hand when it comes to buying and getting better prices. It pays to become proficient in your hobby.