I can not say for 100% certain since I have not seen this specific item on someone in game. However, I DO have the arcstone made chest for my monk and it has the same item link graphic and it is a stupid robe graphic when worn. As I said above, I cannot confirm 100% sure that the ToB chest is a robe but from past experience the "raid" expansions since PoP that have had a 2 tier type of armor set (i.e. ornate vs. elemental), the chests have had the same graphic.
I prefer the strappy "monk" look (imagine that, I'm a monk I want to look like one) over the robed "int caster" look and the tunic "druid" look so I've made it a point to notice chest graphics of drops I'd actually wear. So far, the strap graphic chests I have noticed (that are worth wearing IMO) are the PoP chests and the TSS chests. GoD Pressl's chest is a robe, both OoW tier 1 and tier 2 are robes, Tunat drop chest is a tunic, 90% certain the DoN drop chest is a tunic (supple white leather or w/e), 90% sure the DPoB chest is a tunic (it's dru/bst/mnk wearable they wouldn't give strappy look to another class I hope).
Right now I am wearing Mist-Blessed Leather Tunic and will almost certainly /pass on all chest drops until my guild can get the drops for Osh`vir`s Whisperwind Tunic. because everything else better than Mist-Blessed is either a tunic graphic or a robe graphic. =P