and Welcome to the Forum!
We really need a bit more information on your RV before we can help.
I did a quick web search on a Real-Lite motorhome and I'm guessing it is a Class C on (most likely) a Ford E350 van chassis. If you can verify that and let us know which engine you have and if it is fuel injected or has a carburetor (Ford did both in 1987), one of us should be able to help.
Lastly, just what information on the fuel pump are you interested in? If you think you may need to replace it and if it truly is in the gas tank, then the tank usually has to be dropped out of the frame to replace the pump.