I say we probably wouldn't miss a sidearm because most of us have a gun aside from the Las Carbine (Commissar has a Bolt Pistol, Weapon Spec. has the Melta Gun, etc.) and the Las Carbine has a good amount of charge packs, not to mention it would be fairly easy to requisition ammo unless the Munitorum screws things up and - sincerely - if the Munitorum screws up a laspistol won't save our collective asses.
Let's try to calculate what was already picked and what's lacking. I remembered the GM added Well-Provisioned so we have no extra equipment points, so let's take a look at the options, since we have 30 points:
5 (grapnel) + 10 (upgrade flak armour to Best) + 15 (whisper-bolt discharger) = 30 points
5 (grapnel) + 5 (clip/drop harness) + 8 (micro-beads) + 10 (flak armor to best) + 2 (chrono) = 30 points
5 (grapnel) + 5 (laspistol plus 2 charge packs) + 8 (micro-beads) + 10 (flak armor to best) + 2 (chrono) = 30 points
5 (grapnel) + 10 (upgrade flak armour to Best) + 15 (add one advanced medkit to everyone's gear) = 30 points
Have in mind that: the micro-beads (earpiece for tactical comms) are a good choice since they'd allow us to remain in constant contact; having a watch always has its uses; finally, Advanced Medkits add +20 to anyone's attempt at Medicae even if you don't have it trained.
Alternatively, getting the Flak Armour to Good would still be a good choice as long as we aren't being constantly shot in the face, since it adds +1 armor against the first shot you take in a round. We'd still miss the cutdown in weight which would probably help our wimpier people, though.
It is also worth noting we'd need to clear up our final setup with the GM.