I found a firearm on gunsamerica that I am interested in.  Is there any way to check up on a seller before I send my hard earned $$ to them?  I've searched around for a rating system
with no luck.

you're pretty much screwed when dealing on g-a...the "honor system" of gun auction boards.

that said, most of the sellers are ffl dealers with stores. contact the seller via email and ask for his phone number. drop a dime and size him up from there, while trying to work a better deal.

i've bought a few rifles off of g-a and haven't got burned yrt.

pay by money order or plastic to cover your ass.

 I've bought and sold several guns on GA over the last three or so years. I bought a scope the other day. I've never had a problem. I try to buy from guys who have FFL's and stores to try to cover my ass.
 One thing I learned is that among antique gun guys the deal of sending your money and then getting three day inspection has been SOP for years.
 Just talk to them on the phone and if you get a funny feeling about them, bail.