That's correct.
For everyone playing along at home: Fusion gives a parameter name to every parametric value you create. Most of them are not named by the user, and an automatic naming system provides the names. It starts with d1, d2, etc. This is because each parameter must have a name, so most get the automatic naming scheme. You can rename them, from d1 to something useful for you like "pattern space", and even be made "favorites" if it helps you stay organized.
Phil Eichmiller
Software Engineer
Quality Assurance
Autodesk, Inc.