Borderline vintage as these cranks first appeared in the early 90's.  These "road" cranks come without landings for an inner chainring, although the pictured set has an inner ring mounted.  A Shimano 115mm spindle length bottom bracket was used, but if mounted as a single chainring the spindle length may need to be shortened for a proper chainline.

Edited from bikepro.com

"Top Line produces a road bike version of their crank arm set, made nearly the same as their famous mountain bike cranks. Each of the arms is turned on a lathe making the smooth and rounded shape. The backside of the arms is milled away slightly. This is so the right arm doesn't interfere with the front derailleur. The top and bottom of each arm is milled with a groove that gradually widens as it moves from the pedal toward the bottom bracket. These grooves reduce the weight of the crankset. The spider is machined from 6.32mm thick aluminum plate. The primary difference in these cranks, naturally, is the spider. On the road version there is no inner chainring & each of the spider arms has the center milled away from the top. The road cranks have same pedal fitting, where the pedal ball is drilled and threaded without piercing through the backside of the arm.  The Road arms are made in Black or High Polished Silver. We found the Road arms to have a Bike-Pro Q measurement of 150mm. The 170mm arm set, with spider in Silver weighs just 363 grams, the 172.5 set weighs 369 grams."