Thanks for the kind words and advice everyone. I got home with the bike just a bit ago and all was well. Owner said he’d never seen anything like it, the tow driver hadn’t heard of it either, and neither of the techs had seen it of course. He said there was no remnant of the valve inside the wheel, there was no puncture either. When they pulled it off everything was ok as far as the tire went, wheel balanced as normal so getting it stopped and off the road kept everything ok.
As for the dealer portion, it’s a consignment dealer that’s known locally for their shop as they sponsor racers, dial in suspension, modify etc. The owner paid the shop time to get the tire re-fitted with the new valve stem, and previous owner stopped in to bring the side case inner bags heard what happened and paid the shop back for my tow charges. Being that their shop did not touch the front tire, and only replaced the rear when they serviced it before selling, I didn’t make a fuss about the fact that I may have had to pay for the tow. I took the free valve stem replacement and tire remount, along with the free tow from the previous owner, and went on my way.
All things considered, I got a good deal on the bike, and despite the underwear I had to toss I have a great bike that will suit me much better than my Z900 for a 2 hour interstate commute 2x a week!