as a dj in the early 70's on AM radio, i was unaware of longer versions of songs..had heard CCR "grapevine" , and 'light my fire' on 8 track..but didn't know much else and we didn't play those anyway..except the short version pf light my fire..eventually started hearing longer versions of songs when we would get promo singles at the station and one side would have a short version..usually mono..the other side a long version in stereo..the short side was always played as a rule to get more music in an hour already loaded with spots...strangely mcarthur park was played without question at the time..usually as a "bathroom" tune..lol...and it's still one of my all time favorites..i always play the long version on my internet stream as thats what listeners like...recently stumbled on a long version of SANTA ESMERALDA'S " Don't Let Me Be Misunderstood"...and it is stunning...