[Baertram]

You can get the styleId from the itemLink

* GetItemLinkInfo(*string* _itemLink_)
** _Returns:_ *string* _icon_, *integer* _sellPrice_, *bool* _meetsUsageRequirement_, *[EquipType|#EquipType]* _equipType_, *integer* _itemStyleId_

--or via
GetItemLinkItemStyle(itemLink)

* IsSmithingStyleKnown(*integer* _itemStyleId_, *luaindex* _patternIndex_)
** _Returns:_ *bool* _known_

I think the _patternIndex_ is the itemType then, like hands, head, etc. so maybe it's the same as EquipType, but I doubt it.
I guess you need to map between the 2 somehow: EquipType -> itemStylePatternIndex

I never used those functions so far. Maybe spy other addon's code, like CraftStore.