Yes I have heard of Smoke on the water and Tokyo. IIRC Smoke came out when I was in the 6th grade. I didn't start buying albums till I was like 14 or 15. Before that I just listened to Radio top 40. I was never into hard rock, metal or heavy metal at any age so the only songs from those genres I listened to were cross over songs.
I was always more of a pop, soft rock, blues, jazz and classical listener. Give me the Beatles, Monkees, Beach Boys etc and throw Led Zeppelin, Black Sabbath, Deep Purple, and Ozzy under the bus so to speak.
Since I didn't like much of their music consequently I didn't buy their albums nor even look at them in the stores. So I can't rightly say I have ever seen that DP cover in person.