Nick, I doubt that for a few reasons. One, radio waves mostly go out, not down. Two, with a radio tower on he roof, there would probably have to be some shielding below it to keep exposure down to a safe level. I'd imagine that inside the building is a pretty bad place o pick up the station.
I do know from firsthand accounts that TV reception inside One World Trade Center (the north tower with the antenna) was horrendous. I doubt much would be different with the Citicorp building.