A system of smoke candle launchers was used on Panzers in the mid-war period. Launcher arrays were fixed to the outside of vehicles.
This is what a launcher looks like when empty (the 1st image) and when loaded with the Panzer smoke candle (the 2nd image). Note that this smoke candle has a flat base with a gentle depression. The candle's trigger is at its other end, wired to a firing circuit.
Due to the exigent nature of frontline existence, these launchers are sometimes seen with other contents. e.g. this one contains the infantryman's version of a smoke candle, which has a handle. The launcher can fire it but it generates less smoke than the Panzer version.
And after seeing hundreds of relevant photos, I can attest that this is a very unusual sight. These launchers contain infantry-version smoke candles with their triggers pointing outwards. They cannot be fired from inside the vehicle, so this crew must be using the launcher pots as storage.
In this kit, Rye Field provide a selection of smoke launchers, both loaded and unloaded. But the "loaded" versions are strangely inaccurate. They have a central bump, and beside it a hole. These parts don't represent any standard configuration of the smoke launchers, although they do resemble the very rare case of launchers with infantry candles stored in them.