tested, it doesn't seem to work
submitted a new thread to request it (is that ok?)
link: https://forums.minehut.com/topic/23585-missing-api-for-heads-inventory-headspluginapi/
sad ( ó ︿ò) but i realise it's not necessary, since another plugin has access to that database, along three others.
issue is, i think that we're missing the API for it lol
i'm testing it now to see if it's included. will report back