Originally posted by ogl 645D has the same battery like K-5.
It's new item. Discussed at Korean forum. No links, sorry.
So you don't know what it shipped with (maybe the K30)
Not sure what the 4th pin is for, maybe it's a proprietary connection thing to make it harder for the Chinese to knock off the battery (like sony does) so Pentax can get 8 times as much from you for one battery
Edit - Canon has batteries with 4 terminals as well. Perhaps the 4 posts is because it's actually 2 cells inside and a 4 post system will allow a faster charge.