My LBS does fittings all the time... not just for bikes that you buy new there. Both my hubby and I have spent time on their fitting set up, and we ended up buying new stems and having a few adjustments made.
I would think that if your shop is service orienteed at all ( we all know some are, some aren't) that you could get tuned on your fit, regardless of where the bike came from. And if you don't need a stem or anything else, buy a few pairs of socks![]()
Irulan