Does a 1994 camaro z-28 have posi rear end?

No, a 1994 Camaro Z28 did *not* have a Posi-traction (limited-slip differential) as standard equipment. It was an option. Many Z28s were sold without it. To know if a specific 1994 Z28 has a posi-traction rear end, you'd need to check the vehicle's documentation (window sticker, build sheet if available) or inspect the differential itself.