I don't think our Tin Cans can be A-G fitted. Many moons ago, during one of my holds, I took a group of DESO staff through the Lamella hangars at Shawbury. Among the Wetdreams, Cranberries and Hawks there were a large number of Tin Cans. When we suggested selling them to a third world dictator the DESO smiled wryly and said that we'd deliberately ordered Tucanos sans hardpoints to save cost, weight, fatigue (how ironic...) and possibly as an exemption from the CFE treaty. He said that we could have sold the whole lot three times over if they were weapons capable - at the time the UK Tucs with the Garrett were a lot punchier "hot and high" than the PT-6 versions.
Apparantly you could re-wing them, but the cost is prohibitive.