@annaloog: What you record as an "Ⓢ at 9 o'clock" or "➂ ... at 9 o'clock" should really be a small 2, i.e., take 2. That small 2 should appear on both runouts in the same position because both recordings are take 2s, at least according to (DAHR).
A take 3 of the B side (Rigoletto Quartet) was recorded, but destroyed.
The small numbers that you usually, but not always, find in the 9 o'clock position on Victor records are the take numbers. They would definitely be worth reporting since different pressings and reissues can sometimes be identified because they use a different take than the original release. If possible, everything stamped into the runout should be reported in the Notes.
The even more minuscule number and letter combinations in front of the catalog numbers on 1920s Victors probably identify different stampers.
Norman Fields, who is a member of this site too, has written a couple of excellent articles on the production process and the runout markings of 78 rpm records in general.
The monthly trade journal The Talking Machine World received lists of new releases from the major record producers each month and published them as "Advance Record Bulletins" or "Latest Record Bulletins". These listings are not exhaustive (for example, they rarely include niche releases such as foreign-language recordings) because the companies probably had to pay for them. Usually, though, it is safe to say that a record was released during the month in which it was listed in The Talking Machine World, which always came out on the 15th of the month. Sometimes, the companies even listed the exact release date on which the record would appear. One word of caution: A record listed in, say, the September TMW issue as part of "Advance Record Bulletins for October" would have actually been released at some point in mid- or late September.
... Do the runouts by chance show a little 2 in the 9 o' clock position?
On side A, yes; on side B, it's at 3 o'clock (with 10000B at 6 o'clock) ... had I been aware these numerals were significant I would have mentioned them. FWIW, there is a near-microscopic '6 J' to the left of the 10000A stamp, and a similar '5 O' to the left of 10000B.
So, Talking Machine World indicates actual release dates, then?
By the way, even though both of these tracks were recorded in 1917, this cannot be a 1917 release. Victor didn't start releasing Classical recordings as double-sided records until 1923, and this record was then released as the first offering in the new 10000-series.
Question: Do the runouts by chance show a little 2 in the 9 o' clock position?
This version of the "Lucia Sextette" was probably intended as a remake of Victor / Victrola 96200 from 1908. As early as 1912, Irving Berlin had written a parody, recorded by Billy Murray and friends on Victor 17119.