The bolt circles look a lot like my SR Silstar crank that has a 118 BCD small ring and a large ring that was well beyond 151 BCD Turned it into a single speed crankset with a 52t 118 BCD ring and left the outer holes empty.

The chainring bolts were also smaller diameter than standard and I had to drill out the holes to mount the new ring.

Look here for easy BCD measuring