Being preapproved does mean that they have reviewed your credit file and you pass their initial screening. Not a guarentee, but you have a good chance.
My brother received a "preapproval", applied over the phone and was instantly approved for $4000 with a 700 transunion score. He made me an authorized user,
I received an "invitation" two months later to apply, I did and was denied. So yes, "preapproved" is a much favorable solicitation. I say go for it!
