i have done a small amount of C#, and have yet to work out when you should have a property rather than a normal pair of accessor methods, so for consistency i would have thought always using properties was easier, so you only need one autotext rule.
I hadn't spotted this before I posted an identical suggestion to the Beta forum. Using properties is preferable to accessor methods because it's a well-known idiom and is supported by the IDE as such.
It turns out the default autotext item for C# Refactor Encapsulate Field looks like what you want it to be - but there is a bug in adding the default per language items.