If I'm understanding this correctly, it's not really the bass (or number of knobs) that dictate what band preamp you have or which you can replace it with. ddwilkins did have a 2-band eq replaced with a 2 band eq. However I have the same bass and went from a 2 band to a 3 band. I just bought the model of the preamp I wanted that had the mid and treble knobs stacked. I didn't have a switch so I also opted for the switch built into the mid knob. Of course this meant I had to purchase different pots to accommodate the stacks and switching. None of this was a problem for me since I do my own electronic work. However in general, you can purchase a model of a desired preamp to fit your knob/switching needs.
Browntree
And David spake to the chief of the Levites to appoint their brethren to be the singers with instruments of music, psalteries and harps and cymbals, sounding, by lifting up the voice with joy. I Chronicles 15:16