No, I’ve not moved on. My brain is still fast at work, but at least I’ve started adding things to the actual publication file not just this blog.
No specimens in CRRO. Three in the Schaefer Archive.
None of these seem to be the specimen known to Babelon and illustrated by Gruber
Bahrfelt knew the specimen from the Capitoline Museum (originally in the Bignami collection). Ricco reported (p. 178, no. 27) a quadrans with the legend DOS…
Another appeared on the market in 2019:
Four known weights averaged:
Riccio records a Semis with DOS and Gruber includes, but Bahrfeldt decided in the end it probably doesn’t exist. UPDATE: Thanks to William in the comments below, you can see a photo of what is likely to be the same coin owned by Mabbott and published in 1945:
There has been some attempt to link other types with RVB legend to this moneyer or his family but this isn’t currently accepted. I will note that HN Italy 2675 weight and S on the obverse would make it fit into the series as a semis… There is supposed to be examples HN Italy 2676 (turreted goddess/lion star/ RVB) in Oxford and Paris but I cannot find illustrations and its not linked in IRIS. Nor can I find any in trade.
Liv Mariah Yarrow 
The Riccio semis with (DO)S does exist. It was purchased by Mabbott in the 40s and published by him in the Jan-Mar 1945 issue of Numismatic Review (available on NNP), with a photo as well as the size and weight (in the notes – 23mm, 6.25g). Mabbott thought that “(L.R) VBRI” was below the prow, whereas Riccio left this blank in the initial plate, but changed it to “ROMA” in a later edition. Having seen a color photo from a recent sale, I don’t think its clear which is correct. The proof (of sorts) that this is Riccio’s specimen can be deduced from reading the coin’s description in the first and later edition. Initially the reverse is absent-mindedly described in part (another S), which makes no sense until you see this coin, where the only clear reverse text are the 2 s’. The description was changed in a later edition.
Sorry I am so late seeing this! I am very very grateful for this information.