Not sure I understand what you mean... I've got all kinds of Jackson's and not a single one of them has the same distance from the neck pocket to the bridge. King V and Rhoads neck pockets goes deeper than the neck pocket on a Soloist.
Why would need that measurement? Some Jackson necks have the fingerboard flush with the neck. And some have the fingerboard protruding from the neck. In that case, the neck pocket is smaller, and the distance from the bridge is longer... Jackson uses different type of neck pockets; some are square, some are rounded, some have short heel, others long heel. The fingerboard length after the last fret can be longer, or shorter by a few millimeters. Not a big deal, but that would make that measurement unusable.
Ever tried using a Jackson neck with a locking but, on a body that uses a Tune-o-Matic? It won't fit either. Because the distance from the nut to the bridge saddless (read scale lenght here) is different.
Like I just said, that would be impossible to do. Because some necks have slight differences that would make a good intonation and proper string-to-bridge alignment impossible. And what about the neck screws holes? Maybe they will line up, maybe not. And believe me, I tried it. All kinds of Frankenstein Jackson, and 99% of the time, you have to shim here and there, relocate the bridge, change the nut because it is too wide, or too slim.
Remember that big companies like Jackson makes thousands of guitars and necks per year. They often make small adjustments during the production. A 2007 japanese DK2 neck might not fit on a 2008 DK2 body...