I think "early" and "late" are too general of terms to answer this. Most changes were engine related - cylinder head, e.g. - and you have to look at engine serial number to determine when what changes took place
It also depends whether it is a manual or automatic and what country spec the car originally is. For the exhaust, I believe, you should be OK. No change that affected this. Other parts, you need to look at one by one.