Best I can tell, that thing is based on a Webley Schermuly launcher, it's made out of aluminum and it's meant for launching flares, teargas, etc.
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That's not to say you couldn't use something lethal with it, grenades can be launched with "High-Low" low pressure charges, like your typical 40x46mm NATO grenade used in M79s, M203s, Mk.32s, etc, I believe the M79 and M203 even have aluminum barrels, but there's no readily available 37mm shells for guns like these with explosive payloads.
You could maybe cook up some sort of big shotgun style load, and while there are 12-Gauge shotguns which feature aluminum barrels themselves, I would strongly suggest to be careful about developing such loads for a gun like this, I wouldn't want to test that latch or its bearing surfaces too hard.
Mind also that shooting shotgun shells and what not out of stuff like these will tend to reclassify them as Destructive Devices in US law, so if that's where you are and you intend to fool around with one, get the paperwork in order first.
tl;dr yes, but there's some ifs and buts.
If this is for fiction, you could just go for broke and use it for launching a canister with poison gas or something, not like it'd be functionally different from chucking one with teargas.