Okay. You've got the 1.4 Boot ROMs. You can hold down both mouse buttons on bootup and get a little boot menu that allows you to boot into 1.3 as well (if you've got the appropriate ROM image on a partition named WB_1.3:)
My 3000 (which I think is rev 6.2) also has the 1.4 ROMs, but it needs the ROM Tower. Since you're already running without one, you can probably just drop your new ROMs into the same sockets the current ones are occupying. I'd recommend going up to 3.1, though - my thought is that if you're going to be replacing ROMs, you might as well put in the best possible ones available.