The procedure described in the FAQ lets you to have RailClone Pro 1.x and 2.x installed in the same computer, but not mixing Lite and Pro versions.
Is there some reason you want to use the Lite version ? You can download RailClone Pro 1.43 from the User Panel->Previous versions.
If you need RC Lite, would be possible to copy manually the files. Just replace railclonepro.dlo from railclonelite.dlo in the Max "plugins" folder. You will need to install each package at least one time to make a copy of the .dlo files.
If that helps, the files used by RailClone are listed here