Shenrie is right of course, and besides there is nothing good about stock windows which would make it worth your time. Aftermarket windows are made to go in blank sheetmetal and they offer lots of benefits over stock such as screens and that they all open. Stock offer only visibility. Go aftermarket. The work isn't worth it.
If you do decide to try anyway, I think Vivalavida (Username Pschitt, real name Claude) put passenger windows in his cargo van. I've seen pics from a distance and seen the van in person but I didn't look close or ask how he pulled it off.
Oh, and by the way, if you've got a donor SMB why not just do a body swap? YOu get it all then, but it is quite a job. Ujoint can tell you how hard. He separates bodies all the time. He'll probably talk you out of it like he did me.