Yes #2 main bearing has the "thrust surface" built into the bearing and must be fitted to the thrust surface of the crankshaft. The thrust clearance should be checked. Normally if the crankshaft is to be ground, the thrust surface is also ground and the original clearance restored. With undersize main bearings the thrust flange is wider and thicker, so the crankshaft (thrust surface) can also be ground to specs.
