Can't speak for boutique stuff, but it probably was something of the time.
My 91 DB Apex has them, I've got a 91 and 92 Axis, too, and never thought to check. Thing is, BITD, I used my Apex for everything - off-road, as well as commuting and just getting around. At that point I had one bike, and that was it, no spare wheels for commuting so I had to swap tyres for during the week usage.
Although true to form, nothing I ever mounted to it required the mountings, I used reasonable length, but snap-on mudguards for commuting.
Fast forward only 4 years, to the same model of bike, but the 95 model of Apex, no rack mounts or mudguard mounting holes - so nothing on the dropouts or the forks, or on the seat-stays, and no hole through the seat-stay bridge to be able to add a bolt / bracket there. Something I found awkward when I wanted to get some guards for commuting, because I didn't want to be drilling the frame, but luckily found some plastic, fairly good length, that had plastic clips that simply snapped around the seat-stay bridge.