Yes and no ;-) There are wirenuts listed for cu/al splices (notably the purple Ideal 65) Is it OK, depends on who you ask. The CPSC and New York hate them. As for aluminum RX being 90c rated, probably not since it is usually 1970s era stuff with TW insulation. Has anyone seen NM-b/Al?
I'm not exactly sure how old it is.. I think it's early 70s probably, because I know that the mid to late 60s aluminum wire had the cloth type sheathing, and this one is plastic.
It's not the "new age" aluminum wire though becuase that would say "ACM" somewhere on the cable jacket.