I agree with your questions, and have asked them before. Never got any replys either.
I've seen old pictures of HP 70's with what looked like silver grills and the orange stripe and front, and other pictures that look like there was no orange stripe or front. The same goes for styled 70's. 
If Oliver changed the design, why dosen't anyone know about it?
Good luck in your search, if I ever find anything out, I'll sure post it.
Larry Coltrin