Dont just rely on my geriatric memory!
My 12/76 HX (which Im fairly confident is original) is preslite with washer pump on it, & a couple of 78 HZ's I have (one is definately original) are the later motor with no washer pump, it may have changed over at start of HZ, or might have been phased in when the earlier ones with the pump were used up.
I would just be happy with a wiper motor that works!
& check out cars at shows etc, to make a more educated decision