It has a 4 speed manual tranny. At the front of the tranny in the engine bay is a short dipstick, is the for the front gear box and requires 90 weight gear oil? And is the tranny fluid checked by opening a fill plug on the side of the tranny?

the smaller dip stick is for gear oil , the front deferential .  80w-90  will work fine .

The dipstick is for checking the level of the whole tranny, not just the diff.