The bottom end of a B230F is very stout. Further, if a rod bearing were to go bad, I would put my money on cylinder #1 or cylinder #4, not cylinder #2. But, it is not impossible.

Are you sure that this is not a case of piston slap? Piston slap is most pronounced when the engine is cold and usually stops when it has reached operating temperature.

I am concerned that you were able to isolate the noise to just one cylinder. The only way to know for sure is to drop the oil pan and have a look at the rod bearings. Also, your oil pressure should be low if you have worn bearings. Have you checked the oil pressure? Have you check compression?

If you find a bad set of bearings, you could always pull the crank and replace all of the bearings. This is probably less work (and less money) than dropping in another engine.