It is available in the URL when you open the model in the workshop from your private library.

Aw poop, how do you know if your project is private or not cause I don't seem to find the alpha code.

Sorry for the questions btw.

A model or project is private if it's not published to the public library. 😃
From your own account library (click your name in the header > library), open the model you want in the workshop.
Then in the URL, you can find your alpha code.