I just looked at mine and the RAS-2 manual is exactly the same as the RAS-5 manual except for contract number. Except for the cover page, the pages are identical. The manual cover pages say RAS-2 and RAS-5 are identical to RAS and all the internal pages just say RAS.
I’d bet the RAS-4 manual is the same too.
I don’t know about differences but the Navy electronics catalog says all models are the same except for nameplate and contract number.
There is a RAS-2 manual here
My notes say I have a RAS-5 manual that I can scan. Let me know if you need it.