I'm not sure the 1st batch of Primus-trained gunners have even
ORD'd yet - have they? Even if so, it's unlikely that the weapon
has been extensively introduced in the reservists - maybe in the
near future, but it's still early days.
Until then, the unit concerned may have to convert weapons. I
myself joined another (IHL) unit after ORD, but my former NSF BN
couldn't continue with the old M113 SP Mortars cuz they don't have
it for reservist. The unit ended up spent its final "active"-time
weeks familiarizing with the towed mortars, which consisted of
field exercises & proficiency tests.
It was mostly the same with past 155mm-howitzer units when they had
to switch from the M-71 to the FH-88 to the FH-2000. FYI Reservists
still presently train with the latter 2 weapons. The M-71's from
the 1970s were supposed to have been phased out long ago, but some
military watchers speculate the SAF still have them stored away
somewhere.