Made up UUIDs like 00000000-0000-0000-0000-000000000000

I'm writing an application that uses UUIDs to identify datasets. There is no import of foreign UUIDs, all UUIDs are generated by the app.There is a default dataset that I like to recognize easily as a human being.

As 00000000-0000-0000-0000-000000000000 is equal likely as any other generated UUID, would you say it's ok to manually chose that as the UUID for my default dataset?

Or even consecutive ranges of UUIDs for some chosen datasets?