One of the positions available on the NG3/Dbird switch is bridge+middle in parallel. If you put the neck pickup wires where the middle ones currently are, you'd have bridge+neck in parallel (Jazz wiring) in that position instead. That would of course throw off two of the other pickup settings, but you'd at least be able to evaluate what the Jazz position would sound like without having to buy or install anything. And it would be easily reversible unless you decide you need the Jazz setting more than the other 3.
This depends on whether solder hackery for the pickup shield wires was done. Unfortunekty the switch isn’t one wire per screw connector and they suggest soldering to a common wire.

