OK found a couple of pics but nothing much.
The 60mm mortar looks to have been mounted on the tripod at the rear (+/- 50 cal) and there also seems to be a Mk18 mounted on the occasional rear 50 too.
I'm inclined to provide an additional Mk18 to add to the 50 cal (As that's easy!) but not the 60mm as it doesn't seem to haev been common enough to photograph.