"I don't know that concealed carry was viewed in 1787 the way it is viewed in civilized parts of the U.S. today. I think at least the Founders might have thought there should be no need for an honest gentleman to conceal his armament."
Whether there was a perceived need in 1787 or not is irrelevant. The point is the wording of Article II. "...shall not be infringed" means precisely that.
"...if a state or municipality regard the open wearing of armament as a breach of the peace, I would say that they must of necessity then allow people to carry discretely."
Again, utterly irrelevant. It is explicitly and very clearly NOT up to the state or the municipality. The freedom to bear arms is written quite explicitly into the Bill of Rights, without equivocation or qualification.
According the the Founders, as enshrined in the Declaration of Independence, rights are not "awarded" by the State, they are the birthright of all men, "endowed by their Creator with certain unalienable Rights.... That to secure these Rights governments are instituted among Men, deriving their just powers from the consent of the governed."
Article X, meanwhile, makes quite explicit that the states are barred from assuming powers prohibited them by its textual provisions.
"Shall not be infringed," in other words, means precisely and exactly that. Article II doesn't refer to "concealed carry" nor does it refer to the State's, or the states', preferences in the matter. Those are irrelevant, and there is no "wiggle" room.
My suspicion is that given a choice between requiring that people who carry do so openly, or requiring them to carry concealed, many politiciains would rather requirement concealment.