u/Flamingo-Otherwise

Hi all, im a bit stumped on this. Hoping someone could help out. I bought a 1997 e36 318i sedan. The previous owner had replaced the MAF with a new unit part no. 13627558785 but ive started to notice idling issues. (Rough start, idles at 1100ish, random short revs automatically, etc) they've always kind of been there since i got it.

Anyways, theres two versions of MAF on realoem. One for with catalytic converters and one without. After checking my chassis number my model doesn't have a catalytic converter. So my question is, has the previous owner replaced the unit for the wrong model? Should i be getting the unit with part number 13627547980? Or is the current unit correct?

Please help, thankyou!