That's good advice.
I've heard many stories out Volvo shops saying "hell no", and even picked up a car or two from "Volvo" shops after they screwed it up or gave up on the car. At this point they may not have any more expertise than anyone else. Volvo hasn't used K-Jet in 30 years.
What you will find is that some shops may be adventurous and competent, most are not adventurous (i.e. don't want to risk screwing up something they can't fix, or will take more time than they can bill for) or are just incompetent.
Depending on your issues, another worry is that most shops of any sort have never seen or tried to bring back to life a car that has been parked for 20+ years and they have no idea how much damage that can do to a car.