I'd disagree only that the bike is wholly original and dates from the early to mid '60s--the tail end of the tank bike era. That chainring can actually be traced back quite a ways (mid-'50s, at least). I believe the Ross DeLuxe, Super DeLuxe, and Custom were a contemporary of the Murray "space/flight" bikes--one of TRM's gender tanks would feel right at home on this frame.
It appears strange to me how the sheet metal stampings have weathered so much differently than than the tubes.