Phew, a 10-year necrothread. Haven't had one of this magnitude in a while
It should be possible, yes, though likely not by converting this mod but by recreating it (since the items table this involves differs very drastically). At a glance, since I've never tried for this particular outcome, it seems you'd likely need to go through every weapon and change their Container Unittype field to "any". If that doesn't suffice, changes to Unittype may also be needed (changing eg "[faction]_gun1h" to a valid factionless alternative, like "gun1h" if it's accepted).
Though of course what'd be safer would be to examine exactly how this mod did it, and then replicate that in the Steam files. This is just how I assume it was done.