A detent is a mechanical feature of the pot, and has no effect on the taper or electronic function of the pot.
You can use a pot with a center detent if you want, you will just have a useless detent to mark 50%.
Something worth noting however, I found out that the Aguilar OBP-1 was designed to work with an audio taper rather than linear.
I thought that it was odd as hell at first for an EQ, but then I started thinking about how difficult linear taper 25K pots are to come by.
It may be possible that your preamp is designed to use audio taper pots as well. Linear tapers may work better, or they may give you an uneven boost.