The short answer is "no"; the SMLLC never filed on 1120S.
The complete answer is a bit more complicated (although I don't know if it is relevant).
The SMLLC has previously filed Form 1065 because I thought that would be correct because I thought there were two partners. But since the other partner was my wife, it turns out that it is still considered a SMLLC. After filing the 1065 I received a letter from the IRS telling me not to file 1065 but "in the future, report the profit or loss on your individual income tax return."
However, in 2020 (the tax year that I'm currently working on), after I transferred the rental properties from the SMLLC to myself, and then from myself to a new MMLLC, I added a proper partner to the SMLLC so it became a MMLLC; so I am filing a 1065 for both MMLLCs. The old LLC, which was a SMLLC at the time that I transferred the rental property to myself, is now a MMLLC that owns no assets - it just provides property management services.
