Maybe searching for "calibers" instead of "calipers" did not help.
It's not a spelling bee here, but when searching, it is a good idea.
The seal for the halfs is available, no problem. It's not like you killed your calipers. Just put them back together.
When using air to push them out, restrict travel with a piece of wood, if it can not go further than 10 mm, it won't hit you in the head either.
Rebuilding calipers is pretty easy, overall.
George