Is it safe to assume that anyone wishing to learn Rust can, by alpha2, study The Rust Programming Language and Rust By Example and not need to relearn anything within that scope after 1.0 lands?
The core language is almost completely fixed, and the only real changes will be in unstable areas like associated types. There might be some small API changes but all APIs are marked with stability levels so you should be able to figure out what is stable, and what is not.