Once you start getting into alternate tunings most people use singles to put together string sets.
Red Silk at the tuning posts but nothing at the ball end could be GHS Bass Boomers. They certainly have enough singles available in gauges to do that tuning.
Now, I cant tell by the pictures, but if the bass is Thru-Body like some music men are, they could be Rotosound swingbass 66's which can also be tuned like that with their available singles.
THe silks are in the right place for GHS Boomers going thru-bridge and for Rotosound Swing Bass thru-body.