PFS does not have a very good reputation, I’d simply stay far away from their products.
But no, you can’t lock Motion created templates, but not all templates are created in Motion.
Some Templates are made in Motion, and you can modify them.
And some templates are coded with FxPlug and Xcode, and you won’t see them in the Motion Templates folder, you can’t open them in Motion, you cannot alter them. Unless you’re an experienced programmer and know how to recode them.
Simple as that. They may be coded thus you can’t alter them in Motion. This is true for any developer.
Again, I’d not trust PFS products at all.