I was arrested for openly carrying on my property a month or so ago, and can tell you this... if the officers arrive at a scene of a potential crime, and if the man that called 911 is involved, they do have the right to secure the area and the person until they can find out what is going in. But once they DO know what is going in, then they MUST return his firearm immediately - and that is what I have been told. If it is true or not is unclear. I do know that they cannot disarm someone who is NOT involved but is just nearby - no reason for a terry stop, no suspicion, no permission to violate rights.
I had a discussion about this with an officer in Oklahoma once, and he was unsure himself about how it would play out if they allowed open carry in OK. What was one option that was discussed was that they are allowed to temporarily detain someone if they feel they are involved in a crime in some way, in order to evaluate the situation. So I would think that they could temporarily disarm someone for the same reason.
The question though is can they disarm you at random to just "Check you out."
I would say no. A terry stop requires suspicion of committing or intention of committing a crime, right?