Yes it is also grounded on the body... the instructions give 3 options for tachometer signal hookup and option #1 is to connect the wire directly to the negative post on the coil... it doesnt mention anything about taking the ground off the body if hooking the signal wire there though.. other options are for a brown wire with an inductive pickup either on the coil wire or spark plug wire... i don't have a brown wire connected.
Maybe I'm reading or understanding something wrong though.
Product Manuals
