Do 2003-08 rear headrests fit in 2009?

[jperiod]

Would anyone care to measure the gap between the spokes/holes for their rear headrests in a 2003-2008 model Vibe? We just bought a 2009 that has no rear headrests and were told they were "optional." I figured there'd be plenty of affordable replacements available, but so far that isn't the case. I see mostly 2003-2008 headrests anyway. Are there any other car model headrests I should look for that would fit? 2009+ matrix? What about corollas?

[SeattleJeremy]

Headrests are not optional, they are required safety equipment.

http://en.wikipedia.org/wiki/Head_restraint

[Head restraints] were mandated by the U.S. National Highway Traffic Safety Administration (NHTSA) in all new cars sold in the U.S. after 1 January 1969.

The Matrix has the same headrests.
I could not find find a ruler here at work, I hope someone else can measure this for you.

[jperiod]

Just to follow up, they are not interchangeable.