Yes, people who were 35 or so in 1970 would have been born about 1935, and thus would have been members of the so-called "silent generation" (who came of age in the 1950s) rather than the so-called "boomers." Thanks for making that point, as I hadn't really thought about it in those terms myself.
And, yes, Company does make a few feints at being 1970s "timely," as in the pot-smoking scene. But pot-smoking scenes were, if not already a cliché by 1970, well on the way to becoming one. There'd already been one in Hair. Hell, there'd already been one in The Fig Leaves Are Falling, plus the ones I'm forgetting at the moment. Probably dozens of them off-Broadway by 1970.