Wait a second. (checks wiki)
"Use models for ship selection" in the 5.4 launcher is -ship_choice_3d.
Well I was thinking about fighter mounted flak and how those flak weapons need a model file (which is typically Hornet.pof, so I'll ref it here). The problem is that, in the loadout screen, the Hornet.pof will show even though it's a primary weapon, which makes the whole thing look kinda "off".
What about leaving the "$Ship_icon:", "$Ship_anim:" and "$Ship_overhead:" tags blank instead, and then turning -ship_choice_3d off?

That way the flak weapon will still use the interface art, instead of forcing Hornet.pof to show in the Loadout screen... (that's assuming there is interface art for the weapons...) besides, as far as I know, the regular SCP build auto-generates the loadout screen... and it'll just use a rotating ship model since it can't find the ship_anim for use in the Ship selection screen...
Again, it's just my thoughts on fighter-mounted flak and the Team Loadout menu...