Part of the problem here is defining what a 'crossover' actually is. As far as I know Toyota were fiddling and changing things all through production. By the strictest definition the few hundreds cars were Mk1a and the last few hundred cars were Mk1b. Everything in the middle could be thought of as a crossover.

My definition has been when (or if) the major mechanical parts (engine / suspension) wound up in the 'wrong' shell. Personally I don't think of a skirted Mk1a as a crossover because there were probably more of them then non-skirted ones. It's all a matter of opinion really.