The truck cabs fit all series. One small difference is an 88 as you need a filler plate. Whereas on a 109 the truck cab sits on the bulkhead as the bulkhead is further back.
The series 1 truck cab is unique to the series 1 as such I doubt there would be any confusion or need to ask would it fit a series 1. As most series 1 owners are also very particular on period correct parts I doubt someone would ask if the more common truck cab shape would fit a series 1 as it would quite obviously look out of place especially as a quick Google search shows a very flat truck fitted to series 1 and then series 2's onwards all looking rather similar. So to answer your question no a series 1 didn't count in this thread as common sense would dictate that a series 1 truck cab is completely different.All Series ? Even Series One ? Or don't they count ?