It's certainly possible to use the same size neck blank for different scale lengths, but as Ilan says, they would have different numbers of frets. On a 34" scale 20 fret neck, it's 23.291" from the nut to the 20th fret. On a 32" scale neck, it's 23.020" from the nut to the 22nd fret. This new bass only has a 20 fret neck, so in this case it can't be the same size neck blank as 34" scale neck.
For any given scale length, anytime the neck is sunk further into the body (to improve balance or for style or any other reason) either the bridge has to be moved back or the neck has to be longer and have more frets. For example, a 32" scale 20-fret neck is 21.921" from nut to the last fret. That means there has to be 10.079" between the last fret and the bridge. You move that neck pocket deeper into the body, you have to move the bridge toward the butt end of the bass by the same amount because you have to maintain that 10.079" difference. But if you used a 32" scale neck with 22 or 24 frets, the distance you need between the last fret and the bridge will be shorter, so you wouldn't have to relocate the bridge as much or maybe not at all.
Hope that makes sense. The caffeine hasn't completely kicked in yet.