Did the seller tell you it was a 1911? I find it suspicious if the current owner called it a 1911. When I see somebody in possession of something like that with that little knowledge I think they probably stole it.
I'm not an expert on hi powers, but I keep a pretty close eye on firearms in general. I'm not going say what I think it's worth, but I tend to agree with what everybody else has said. Sometimes a gun is worth more to you just to get an off the records face to face gun. If you think you are going to flip it then you need to look long and hard at how much they are selling for.
Btw, I remember back in about the '90s browning put good * gold triggers in a lot of their guns, rifles, shotguns, etc. I don't think it was a big deal, it was kind of brownings thing. Again, I'm no expert, but I remember that. A friend of mine had a bolt action rifle with a good * gold trigger, he thought it was special also.
* F'ing auto correct!