I have never owned one so I am not sure.
I assume it has an inflation mechanism similar to the automatic life vests. As you are aware these do need periodic replacment of both the CO2 canister and the water
detection/auto firing mechanism.
I would take it out and have a look, but it might automically inflate as the canister opens. If it has a manual inflation like a lifejacket the first stage is to blow it up by mouth and check it holds air for a couple of days. If it passes this test see if a reaming kit is available.
Then try throwing it in the water
and doing a MOB
drill. Nothing like practice and learning
how to use saftey equipment
If it was me I would also tie it to a big fender
. A Jonbuoy is much easier to see than a fender
, but fenders at least give some flotation to the MOB
victim and they provide a backup marker if the inflation mechanism fails which is always a slight risk with a product like this even when new.