Whether it's been in clearing before doesn't tell you whether it will be in clearing this year. Clearing is ultimately dependent on the applications and cohort in a given year and so varies massively year on year.
You just have to be ready on A-level results day (when most courses are added to clearing) to be up early and ready to check the unis your interested in applying to, to see whether they have the course you want in clearing, and call as soon as the clearing phone lines for that uni open.