Anyone know?
Google results turn up a blog entry that says the first Petr Kavka came in the 6th run (I think it’s a typo and was actually the 5th run as Jerrod said) but was actually the only 66g release of the run while the rest were all 65g. The 67g Whale definitely looks like it came from the 7th run.
edit
Just found a January 2012 blog entry for another store that shows a Petr Kavka Chief that is supposedly the “lighter version” as well.