Hi David,
If you manage a DNA test for a deceased individual and you also manage the individual's profile here, you can add their DNA test info to their profile here, including a GEDmatch test ID, if applicable.
WikiTree policy requires living individuals to enter their own DNA test info on their profiles here. Living individuals can do so by joining WikiTree, at least as a Family Member. They can also include their GEDmatch test ID at that time.
As Peter indicates, when the WikiTree/GEDmatch connections are eventually re-established, then any such WikiTree link should be reflected in the corresponding GEDmatch reports, assuming that option has been enabled in the settings for the particular DNA test at GEDmatch.