Ok, I deleted what I just wrote. You have a cord now that has a male on one end? (shore power pedestal end) and a female end on the other end of the cord, that plugs into a (recessed) male plug hardmounted on the vehicle? and you want to take a standard 30 amp RV cord and put another FEMALE end on it to mate to your vehicle?
If that is the case, yes, you can, and you should not have any problems. You may have a power management system that reports a dead input (L1 or L2 depending on how you wire it), and only part of the coach would be powered. You could add a L1 to L2 jumper to solve this, but a good EMS might report problems when it sees the same phase or waveform on one side, dunno, don't have any experience with this part of the equation at all.
Charles