If you want to be trained to slot people, it's definitely the wrong profession...
At BRNC, there is a basic weapons handling element; I'm not sure if there are any weapons handling components to the courses at Raleigh. Even so, most of the RFA will never touch a weapons system again after basic, unless it's a RAS rifle.
The WMO (a 3/O E) has training in weapons maintenance for most of the weapons held on board and some of the lads are trained in firing the 30mms/20mms (for which they need regular re-certification).
At the end of the day, we're professional seafarers who facilitate delivery of 60% of the RN's tasking every year. We leave what's left to the RN/ RM.
Hi we only have command weapons on RFA ships so no need for personal weapons handling test. That said I have done it a couple of times for an instrucotr role at BRNC, but not part of my day job in normal RFA world on ships.