99.9% of the time no, RV bumpers are not strong enough.
Ask your RV manufacturer, only the manufacturer can really answer your question.
Most RV bumpers are nothing more than 14ga sheet metal (1/16" thick), which is only two ga sizes heavier than your automobile sheet metal.
And inspite of a lot of folk who will be chiming in I NEARLY lost a pair of bikes when my bumper started tearing away from the welds. So don't believe the folks that say "I have done it for x amount of years and never lost one", not all bumpers are 14 ga, and that person may have a 1/8" thick bumper.. But yours may not.