I have a series of matrix blocks that use a ton of the same fields and was hoping I could simply duplicate them in the database and update the context and id of the fields. It'd be a LOT faster this way however i'm unsure of the UID column, how/when that is created and if i should leave it blank, or if that column existing means i'm going to have to it all manually
Don't worry about the UID column. Check out this comment from Brad Bell. Craft uses the UID internally, and will add them when needed. You should be fine by leaving them blank.