Yes, you can batch edit manufacturer tags, but not rig tags which is the subject of the request and the primary thing you see when scrolling through or using presets (edit: on the Kemper).
The rig tag is editable and not locked - I'd just like to be able to batch rename them to turn nonsense like 'Hubbly Jubbly Gondwana Mars Attacks L3+' into 'Marshall Silver Jubilee L3+'! 