I assume it is a Shimano dynohub, they are grounded to the fork. SP hubs are not grounded to the fork. Some lights are grounded to the fork or frame, some are not.

If two or three of your new parts is grounded to the frame or fork, wiring it up wrong can mean it won't work. Otherwise everything should work fine.

Put your system together but do not hook up the taillight wires yet. If the headlight works, great. If the headlight does not work, switch the two wires at the light, that should fix it.

Assuming that the headlight works, hook up the taillight and try it. If both headlight and taillight work, you are done. If something does not work, switch the taillight wires, probably easier to switch them where they are plugged into the headlight. That should fix it.

ADDENDUM: I forgot you were using a bottle type sidewall generator. That likely is grounded to the fork or frame. But otherwise it would function the same as a dynohub.