That is always a grey area !, things like that, I always mark them with something.
"Did they replace it , or not"
Some time ago I remember a couple of times the dealer said they replaced it for nothing, [as a courtesy offer I guess], as they made a big deal out of it,
When testing the transmitter, they said the range was low,
Considering the battery is only worth $3, they probable hid the charge of $10 for it in the cost of the service.
And the service was approx. $360,
Keeping in mind, they did charge labour to replace the battery tho.