OEM Sunroof Install Questions

Okay, so I can buy a 4th gen OEM Sunroof, my problem is as follows. Will a 4th gen roof fit in a 5th gen max? Can an OEM sunroof be installed aftermarket. If it does fit, is it a good idea to have it rebuilt. Is the sunroof the same size. Please let me know if you know, preferebly if you have done this. Thanks, Chris