Well, I generally err on the side of too much information, particularly if it is to keep the contractor on the right track for what they need to install.
I think the fact that all the sides are tied together is irrelevant. Considering that every wall (regardless of material) is attached to something. I think at this point, I would be looking at whether this assembly is manufactured as such by a single vendor. If so, then it is likely the vendor will be given specifications or instructions seperately from the plans. If this is the case, then why not simply label it as a "Storefront Assembly" and then give the specifics in the fenestration schedule.
I suppose it isn't a simple proposition, but I suspect I would label a multi-sided front on each side with the label that is most fitting for that subassembly ... i.e. glass or door ... and then spell out the spec's in the schedule.
I don't think there is a wrong way (except maybe not labelling it at all) as long as the contractor is 100% sure what it is supposed to be.