Actually tuners that do remapping/tuning on a dyno start off with a generic tune (previous tune from another vehicle) and load that, then set other parameters that your car would need, this was done with my car when it was just a mafless from a reputable shop here in brissy
But there a some tuners with dyno that will just load a generic tune and give a power run, print the dyno sheet and be on your way
the only way to tell this is with a before and after printout....check the times the runs were done if they are within 1/2 an hour I'd say just a generic so you'd be better off with a cheaper mailorder
Don't be put off by this go and talk to a tuner (eg.chevs/ lsx garage)and ask whats being done its the only way to find out if they want the best for you and your goals