IIRC, Some E30 M3's came stock with red bumper tape, not only EVO III's.
My white 1989 came with red bumper tape.
I have never ever seen this 'stock'. Maybe the PO did it to your White M3 before you got it? I am sure it would have been easy to buy from the dealer back then and put on yourself... but I highly doubt it as a dealer ordered option.