Are those prismatic cells clamped together? I’m not sure why, but I do know they like to be under some kind of pressure. I would definitely look into that before you charge them up!
“Internal forces are constantly acting on a thin aluminum case that is not strong enough to resist these forces. Lack of compression leads to damage of the cells, as indicated by swelling and premature battery failure.”
I looked at the spec sheet and it seems that just taping the cells together like that should provide necessary support for all but the outer sides.
A clamp wouldn't hurt, but probably give me negligible benefits in the projected lifetime of this pack. I'm not using this very often so the pack will age out before charge wear will be an issue. Say I get 300 charge cycles over 10 years, that would be heavy use for my radio pack.
I would look at fabbing up a box that fits snugly, rather than "clamping" them. That could protect against puncture as well. A 3d print or thin plywood glued together would be fine.