It is not. The currently effective class rules are posted on the International Class site, and do not yet include the changes widely discussed and voted on at the 2014 Class Executive meeting.
The new rules, including the ProStart related GPS topic, are pending ratification by ISAF, and WILL NOT be effective until announced, and WILL NOT be effective prior to April 1, 2015, per the International Class website.
I emailed Tim Winger. Here is his response: "The way the rule is proposed, it will be legal. It will be up to ISAF."
I do agree with you Ron that it reads like it will be illegal.