If I had to guess, I'd say that Ron was suggesting having those existing tabs made longer so they could then have additional 90 degree (or so) bends added that would follow the contours of the taillight lens...which would position the tabs the guards screwed/bolted into parallel with the plastic lens of the taillight.
Bosses could be placed on the back of those tabs (the sides facing the taillight) for use with the screws/bolts holding on the guards you're installing, but neither the tabs or the bosses would ever actually touch the taillight lens.
Granted, that would add an additional step if it became necessary to change a bulb in one of the taillights because those mounting pieces would then also have to be removed before being able to pull the taillight off, but, that's the price you pay for having custom $#!+.![]()