i think the stock would fit fine, not too sure about the barrel. as long as you swap the upper and lower receiver together i don't think there should be any issues.
i think the only real difference between the VFC and G&P receivers are the way they lock together. the G&P uses tabs like TM bodies, where as the VFC has a lip on the back of the upper that slides into the back of the lower.
Weapons Technician / Gunsmith
Don't look at me, I don't know, lol ¯\(°_o)/¯.