BUDS doesn't tell what was done, just when a dealer made the effort to say it was serviced. I do know that when we are contacted by a person who has purchased a bike that we have a service history on, we will print out copies of what was done on the bike. So it doesn't hurt to ask where the bike was serviced and contact that dealer.
I do agree that if you don't know exactly what was done, it is an excellent idea to change the oil now and establish a baseline.