"I don't believe there is a 60 day restriction for 527's..."
There is, but only if they accept donations from either corporations or unions. If they don't, they can put out ads right up until the day of the election (barring the last 24 hour period, since that is the time period usually required to verify the source of any donations, which do have to be publically disclosed)
The Swiftvets have not received funds from either, and will not suffer under the 60 day prohibition.
I actually found this out today on the Swiftvet forums themselves.
Qwinn