Sam,
You'd need to ask Avidyne if any of their equipment is the subject of ITAR restrictions (Google it).
It's probably reasonable to assume they aren't however, as if they were, Avidyne would have had to have licensed the equipment to you under a TAA or similar. I should think your gyro-stabilised camera mounts will have been sold to you under a similar arrangement.
The more pressing question is what you do if you require spare parts in-country. I would expect that US suppliers are prohibited from shipping items of any description to you under trade embargoes various.