Mine had this done by Bahnstormer Alton yesterday - it was in for a service, this is when they're addressing it. The bevel gears had an oil change and I believe they opened the shaft up as they said they have other checks to do for wear so I'd like to think they were meticulous enough to clean out debris.
I have to say though, not for the first time I've asked them pointed questions about certain things, in this case I wanted the shaft and splines separated, cleaned lubricated etc and found the answers to my questions almost evasive or circuitous. When I dropped the bike off and asked for this expressly, they said that was part of the recall although the person I spoke to seemed to be giving me the response I expected rather than fully explaining the process. I was prepared to pay for this in necessary. When I collected the bike the next day (they only have one set of tools and are lining up the bikes to work through) they could only answer my question by saying 'everything was within acceptable limits' in spite of my asking for clarity.
It may be that they are doing everything diligently but giving these kind of answers does nothing to assure me of the care I expect and I'm almost tempted to open it up for myself. Many car repairers are providing the customer with photos, why not do the same for bikes?
I'd also asked about the momentary noise that was apparent on a cold start from the RHS cylinder. Answer was 'noted, but they all do that'. Really??
Not long after I got the bike from them (premium used for what it's worth) I found loose spokes on the front wheel and asked for the rear to be checked at the same time as I found plenty of dead sounding spokes in the wheel. The service agent I spoke to couldn't have been less concerned and would answer my questions directly. I never did get any feedback from them regarding the wheel, they never confirmed that it had been looked at either. By his tone on the phone it was clear I was being a nuisance by pressing him for answers to specific questions.
When I bought the bike they hadn't cleaned it properly; the sump guard was packed with crusty mud, it was absolutely solid with it. By the time I got home 2 of three screws had fallen out of the side stand foot and the foot fell off as I arrived on my driveway, the RHS hand guard was flapping about and I noticed that two of the four screws in the screen mount were incorrect. The prep was sloppy at best but it was my first time for GS ownership and I was a little dazzled admittedly. Putting too much faith in a dealer won't happen again.