The Rules Reference booklet says:

"Trooper upgrades add specific trooper minis to a
unit, represented by unique sculpts to easily identify
them. These minis always share the defense value,
wound threshold, and weapons of the unit card they
are equipped to, but may have an additional weapon of
their own."

For example, I have 1 miniature with rocket launcher, and it requires to be exhausted to attack with 3 black dice. At the same time he’s a member of a trooper unit (4 miniatures) whose standard attack is one black die. So when unit attacks (assuming one single enemy unit) I can choose to exhaust him adding 3 black die to the attack pool or not exhaust him adding a single black die to the pool (7 dices vs 5).

My question: If the card is exhausted could I still use the standard unit weapon? Is the weapon exhausted or the full miniature?

Thanks!