I'm curious, did you originally go just for IM? Or did you already know of DT by that time?
Yes and no.. Just Maiden. Maiden was easily my favorite band at the time. I had never heard of DT .. Kinda.
TAC's college radio story again

In college I did the metal show at my college radio station. In 1989, I was going through the new release bin and I came across this album by a band called Dream Theater. It was WDADU. I thought Dream Theater was a great name for a band. I sampled it " on cue". It was interesting, but the album cover was so gay, and the band pic was even gayer! So I put it down and the episode was erased from my memory.
So when I saw them open for Maiden, in my mind I had never heard of them or remembered.
It wasn't untill a couple years later when I ordered their "first" album that whenever I opened it and saw THAT cover. I was Holy Shit that's the band I sampled in college. I was in complete shock!