Cabela's won't let you OC a loaded rifle, but a loaded CC pistol is acceptable - this from the manager of their Fort Worth location after I commented on needing to check in my dedicated .22 AR upper when I brought it in to find a few parts (I had brought in just the upper, sans BCG/CH).
As for the LGS - depends on where you are. Some will let you OC/CC whatever you want long as it's legal, others won't let you regardless of the law.
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That raises an interesting question then. Would those that see Starbucks as Anti 2A/anti gun think the same of a firearms vendor who have the same policy?