Yep-that's a Greco "Companion". Probably his most popular model next to the MST (mid-sized-tactical), which is the knife in the bigger picture above. That's the one that got my interest when I saw it in a knife mag profile of John Greco.
That's an earlier one as already stated. Pre-2000 most likely, because of the brown sheath and the "A" designation.
He later changed them to a thinner profile (0.20" vs. 0.25") and made them in a different steel marked with an "8". Yours has the older gray "crib-safe" finish. Later on they went to a black crinkle type finish and after that a gray "denim" (marbalized looking) that had more of a sheen on it.
Personally I prefer the "old" steel but in the thinner profile so I'm SOL....lol. I think somewhere in the house I have three of them, one from each period...
Great pattern user, enjoy.