I've seen on other e30 m3's sidemarker is the same, or what looks like the same ones, as the ones on the e36's. The side markers on my 91 m3 is the ones that attaches to the both, front and rear, bumper moldings.
Do these owners with the e36 markers installed it themselves ? I just received the Nov/Dec issue of Performance BMW magazine and it seems that all the e30 m3's in the mag are the ones with the e36 markers. And there is no trace of any side marker removal in the bumper moldings. ??????