What causes you concern about their legitimacy? They did a beautiful version of I Don’t Care Who Knows It by Duke Pearson and were all set to reissue Passing Ships on vinyl until Blue Note decided to make it a Tone Poet. Wallen Bink even had three separate jackets produced for the cover art, which were quite cool. They have also released various MPS cuts as cool singles. I own several of these, the Duke Pearson and the three lps referred to above. They all strike me as real labor of love products.
All the details on the Pearson issue:
https://www.discogs.com/release/12924662-Duke-Pearson-I-Dont-Care-Who-Knows-It
Go to their Facebook page to see the alternative covers for the Hill record.