I contacted Ruger's Customer Service to initiate the process, and spoke with a very nice lady, Patricia, who issued an RMA number and indicated the cost of the refinishing would be determined after they had received and examined the gun. They would then contact me to arrange payment; I was perfectly fine with this and was willing to pay whatever it would cost--after all, it was my screw-up. Patricia also mentioned the turnaround time for refinishing work was typically two to three weeks.
According to FedEx tracking, Ruger received the gun on Tuesday, 09/08/15. I waited the remainder of the week for the call from Ruger, but it never came.
Then on Monday, 09/14/15, I got home and saw a FedEx note on my front door, indicating they had unsuccessfully tried to deliver a "signature required" package, and that it would be held at the local FedEx facility for pick-up in the evening. I collected the package from the facility later, and yes, it was my GP100 back from Ruger.
I had sent the gun to Ruger without the grip and hammer/strut assembly to render it inoperable in case it was stolen in transit. Ruger sent back a complete gun that had been beautifully refinished and test-fired. It was refinished to what I would consider "museum quality." The grip they included with the gun isn't the standard Hogue rubber grip found on current retail GP100s, but their older Santoprene rubber grip with laser-engraved wood panel inserts on both sides and brass ferrules on the grip screw. It is a work of art.
Ruger didn't clean the gun after test-firing it, so I completely detail-stripped it and gave it a thorough cleaning. Here's what it looks like now:




Truth be told, the refinished gun looks so nice that I'm seriously considering getting some kind of presentation case to put it in, and then buying another GP100 to use at the range. I'll have to mull over that a bit more.
So, Ruger refinished the gun, added a new hammer/strut assembly, threw in a grip with those gorgeous wood inserts, and had the gun back to me in under a week. All this while charging me... absolutely nothing!
Show me any other company that has better customer service than this.