If you're using active pickups like EMGs, then yes you could use a battery box.
However, if you're using the normal, passive p bass pickups then don't get that hole routed into your brand new body.
When it's asking for the bridge pickup, it means what shape do you want the route/hole to be made for. They're not going to give you a pickup lol but they'll drill the hole in there so you can install that respective pickup into that place
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