As far as I know there are only two ways to know what it came with. And neither is the VIN unfortunately, as older VIN's and especially Fords did not include that info.
The only way is to read the codes on the warranty plate riveted to the glovebox door, OR, if that does not exist anymore, the Marti Report (
www.martiauto.com) for a '68 or later Bronco.
Being a "U" I'm guessing yours is more like a '74 or '75 maybe?
I don't actually know what each letter indicates, but seems like the U's came in after '73 at least.
Paul