I just recently was made aware that there are actually 3 different “builds” of Flex SDK “hotfix 3″ out there.
1. Originally hotfix 3 was applied to hotfix 2 (updating a few swcs) - version 1
2. Late summer 2007 it was realized this confused some folks so the hotfix kb article was replaced with a full version of the SDK with the fixes applied - version 2
3. Flex Builder 3 beta 2 shipped with the latest/greatest SDK from the 2.0.1 branch which is an equivalent to hotfix 3 SDK - version 3.

These versions should be functionally identical afaik.

I updated my version checker to detect and differentiate these versions. I have updated the original blog entry here and also have links to the update AIR app here.