To restore a gradebook on a new GauchoSpace site, you must import ALL materials from a previous GauchoSpace course site. Importing all materials will carry over the previous site's gradebook structure, including any manually-created items and your gradebook's aggregation method and values. Doing a partial import will not carry over the gradebook information into the new site.
See the following article for instructions on how to import from another GauchoSpace course site:
How do I import materials from another GauchoSpace course site?