The manuel for my propane generator in my new RV calls for oil that is rated SJ, SH, SG. I can not find oil?

with those letters on the back of the bottle. Could it be that the manuel is just old, and that the oils listed are just the best oil that was available at that time, and that newer oils like the CJ-4 oils would be all right to use in the generator and perhaps even better than the ones listed in the manuel.
What do you think?