You won't know for sure unless you apply and see what happens. I agree with tauphi that unless you were high-profile, and are on some sort of written list/database, or possibly on a bunch of photos of events they have on file, that you are probably OK. If you are of Tibetan origin/ethnicity/name, you possibly may be up for extra scrutiny. You should not mention on the visa application, any plans or intent to go to Tibet. Once you make it inside China, you can make arrangements to go there if you wish, after first apprising yourself of the restrictions on foreign tourists (who can't pass for local Chinese).