I'm just a dope on the forums, but here's how I presented it in my campaign:
The copy that Luc carried around with him is the "development prototype." I described it to my players as being pretty rough around the edges, and had obviously been taken apart and reassembled many, many times. It was clearly a labor of love, and had the (literal and figurative) fingerprints of the inventor all over it. (Incidentally, underscoring this point really made the PCs feel they've achieved an emotional 'win' against the Ob, having stolen something so valuable to them, not just looted another piece of gear.) I also told them that these little clues would give them a small bonus to Know:Arcana and Know:Engineering to 'reverse engineer' the thing, should they want to figure out how it worked.
The copy in the top of the train was the "production prototype." I described it as physically smaller than the first lantern, but that was just due to cramming the components closer together and more efficient packaging: none of the important bits were actually scaled down (kindof like a laptop versus desktop computer). It also had far fewer scratches and other signs of tinkering. It's also slightly less beautiful, as it if was assembled by a (very intelligent) person following instructions, rather than lovingly handcrafted. I think I also said this one was a bit more durable (higher hardness, same HP), should it be faced with trauma (hence why it can be loaded on top of a train, whereas the other one needs a case). Which can be relevant, depending on how the climax plays out.
Having the contrast allows the players to see that there is an engineering and rollout process at work, and hint strongly that they [the Ob] are about to make a bunch of these.
As far as functionality goes, they are identical, but their utility differed due to packaging:
The "dev prototype" was stored in that huge case that you always see Luc lugging around. I described the inside of the case to have a big foam cut-out for the lantern, but also ten small cut-outs in the foam, each containing a different vial of oil, marked with a symbol on top. This way the PCs were given a couple doses of other-planar-witchoil to play with. I figured he'd keep them together for all those demos he was doing.
The "production prototype" was merely preloaded with (bleak gate) witchoil.