No, I think its fairly sensible, but it depends whom youre selling it to.
Most people dont really want or give a cr@p about the aftermarket pickups, and those that want the pickups tend to want them in a guitar of their choice.
It probably appeals more to both broad groups to sell them seperately (or at least give that option) so you get interest from
- people that want the guitar stock
- people that want the guitar to mod how they want to mod it
- people that want the guitar with current upgrades
- People that want the pickups for their own guitar
I've usually sold guitars as BK upgraded quite successfully and with similar pricing logic (decent second hand prices for both, add up and take a little bit off, depending what it looks like compared to the new stock guitar).
Not entirely sure what the guitars worth but I reckon 120 is somewhere between fair and good for a pair of BK HBs.