Samuel, this truly will depend on the actual firearm and how it was used. The Ruger Police Service Six was top notch when new and whether you get a lightly used or heavily used model will be the ultimate determining factor. I really wish Buds offered a Hand Select Service (even at a cost) for used/surplus firearms. Just make sure you inspect it at your FFL before accepting the transfer and you will be fine. Cheers and stay safe!

The service six is a fixed sight security six and they are one of the toughest sa/da revolvers they were replaced by the GP100 model in the ruger lineup. I would suspect being surplus guns that they have been carried more than shot burt thats just a guess

Yes they are very sturdy pistols. I own the Ruger speed six and have no complaints.

I don't own this particular model but I own a Ruger speed six Wich is essentially the same gun and yes it's very sturdy and very well made. Ruger definitely did a good job making these and most people agree.

This is used so its hard to say for sure, but i can say all the Ruger revolvers I've shot have been solid and well built.
Also this is listed as "fair"
And by buds descriptions fair is "FAIR indicates that the firearm is perfectly serviceable, but the finish may show a good deal of wear, and the grips may or may not be original"
They do offer buds extended lifetime warranty (for purchase at check out) so if you throw down an extra $20 you can be sure this'll run as long as you do.
You also have the right to inspect it at the FFL before beginning the transfer, if it doesn't lice up to advertised conditions you can refuse the transfer, buds will ship it back to their warehouse and then refund your money.
So if you like the pistol go for it really very little risk.