If you can't throw down the money that the dealer wants its best to forget about it. Thing is, gun stores will let those things sit for a long time before they will let it go for under what they paid (most likely he's trying to make 50 bucks off the deal meaning he probably bought it for around 300). If its still sitting there in 6 months he might let it go at cost.

PS I work for a local gun store, I swear I'm not just talking out my butt!