Hey Rue, I saw this post the other day while I was at work and didn't have time to engage.
Pretty cool that they're playing Maiden on the radio! Anyway, you're right, the original mixes of those old songs didn't have all that much bass back then. Remember this was well before the whole "sub woofer" thing started around the 90's. That's why a lot of albums got remastered to take advantage of the expanded frequency range of more modern audio equipment.
I remember back in the 80's people were more concerned with having the best 6x9 speakers in their cars for the punchy mid-range. They didn't have these big bass boxes that you see today. Of course hearing the live music, you get the full range, but the recordings were mostly aimed toward what they could reproduce on the mass consumer's audio equipment.