The B18 with alternator tab first appeared in an Amazon on the 123GT engine. Car had a pair of extra lights as standard and helped to up the electrical spec for Competition purposes. Not much spare room on a LHD but plenty on the RHD cars. LHD cars with A/C meant the alternator went back under the exhaust manifold. Also crossed over to the "new" 144, although I think the very first ones, with B18, were still fitted with dynamos.