This is more of a question of who has to have the "technological device" for Arcing Surge to work with Spellshot. Am I still the one required to have the device or does it have to be the target of the Spellshot who needs the device?
Ideally, your gun would be the technological device overloading for the spellshot. Regardless, it still needs to be in your possession.
I was more concerned if the spellshot would only work on targets carrying a technological device.
No, the way I read it, surge just requires you to have a device to provide the source of lightning. I wouldn't expect that to change with spellshot. Mechanically, it's still just a lightning line attack.