How'd you find this topic, but
miss the recent topic alerting people to the problem, or
the battery list itself which was included in several weekly news emails in the last couple months. The answers you seek are in those two topics.
I can't remember if all versions of Unicron had the plastic slip in them, but they all had their batteries included with the toy. They were all button cell type, which were always included.
(and as noted in the first link above, the plastic slip doesn't prevent the batteries from leaking or even depleting, as it only separates two surfaces out of the 3 or 4 joining contacts - any battery touching another will still corrode/leak/deplete, but the plastic slip just prevents a complete circuit from accelerating it)