To the best of my knowledge, there is no Tamiya 1/72 kit (Tamiya has a kit out there in 1/48, is it possibly that one you're thinking about? A smiley face regarding that one sticks in my mind. I think it's available locally, so I'll check it out). The only way I could think there would be one would be a recently reboxed Italeri kit. There are five or six molds for the A-10 in 1/72, often reboxed under other manufacturers' labels. The kits themselves are often reissued every few years with different markings for different aircraft. Is the smiley-faced one PRKII's plane? I'll dig through some of the reviews and release listings to see what I can find on it.
Italeri, reboxed by Revell-Germany
This kit has fine, recessed detail, regarded as the best.
Academy -- Another excellent kit, recessed panel lines.
Monogram -- Currently the Revell-Monogram offering
Ancient, raised panel lines, but decent.
Hasegawa -- Old, raised panel lines, but decent.
Hobbycraft -- I've seen reviews advising against it.
Matchbox -- Very crude and simple kit.
Here's a new and progressively updated list of 1/72 A-10-related offerings. I'm hoping to do a few reviews for this webpage shortly on the A-10.
http://www.72scale.com/aircraft/Fairchild/A-10.htm
Santa fondles the elves...