Hi Felix.
There is only 3 variations to my knowledge.
1) the type first used 1990-2 when they came as standard with 15" wheels and narrow arches/flares. ASAIK they all had sidesteps and a cut out to accommodate them.
2) The second type is the type fitted from 92 to the end of production with sidesteps, this had the wider arches also the cut out for the step.
3) The third type is the one which fits the 92- which was fitted in the UK GS variant which didn't come with sidesteps. This was only available from late 95 into 96 when it was replaced by the GX model and did have the mudflaps without the cut outs, and side steps.
As a note, If there were any other markets where 80's were supplied without sidesteps that might be an avenue of research that I am unaware of.
As far as I can see I'd say the part numbers of the front mudflaps without the cut outs are 77603-60011 RH and 76604-60011 LH.
Hope this helps.