To the last sentence, attendance records show that the average attendance for 1975-76 through 1979-80 was 16,433 (regular season, I assume). So it looks like distributed tickets has always been the norm. Of course, it's possible back then they had no way of counting the actual attendance (unless there's a counter in the turnstile.)
How did 1970s turnstiles work?
There. Now this thread will never end.