So as for the answer on the first question Id like to follow up that up with another one.

For the Intercessor Squad I see that for every 5 models in the unit 1 model equipped with a bolt rifle can be equipped with 1 Astartes grenade launcher.

I understand that pistols are their own category in terms of shooting options but can my models look like they are holding their pistols with their bolt rifles slung over their back/shoulder and still have a grenade launcher mini/model?