You hit my idea right at the very end of your last post. I would go in to the suspect dealer, price out the exact same setup, and see what he comes up with. If it's very different than the deal that GF got then I would confront him right then and there. If he stonewalls then I would mention going to the local Better Business Bureau and filing a complaint.
I would also take a look at his floor model(s) and see if the serial numbers match up or possibly if one of those serial numbers matches one of yours! If it did then I would REALLY get upset.
Your call on telling the GF. Could go either way. She might appreciate your going for the savings but then she might feel hurt that you had to out-do her & make her present better and not appreciate the present as-is. I've gotten presents in the past that I know for a fact were overcharged but let it go and kept my mouth shut.
Lead Cook 'Second Star BBQ' using a Big Orange 'Prince', 22 OTG, SJS FBA & KCBS CBJ