What happens to machines that missed the OS update and get it after rebase tool is run?

Q: We sent out an SMS package already with the client os update and set it to run Friday at 12:01am. We want to run the exchange calendar tool Friday morning. What happens to machines that missed the OS update and get it after rebase tool is run?
A: You would have the potential that any appointments/meetings created on that unpatched workstation - until it was patched- the appointments and meetings would potentially require rebasing.