Don't know anything about Flint, but most shops don't, or even if they do, they're not going to go very far on something, unless your a regular or draw a lot of water in that particular shop.... and if you were, you wouldn't be here asking the question. Most gun shops are in business to make money, not lose their shirts.
It doesn't hurt to ask but don't be surprised if someone gives you a look of disdain when you try to get the price lowered by $150. It's easier to just shop at places that have what you want at the price you want it at. (or at least can live with).
Also its worth knowing that with consignment stuff (not sure if they do this or not) the shop will probably be inflexible. They want to get their 15-20% or whatever it is they're asking the seller for.
-Mike