In that era, 120 & 620 film size was in common use. These two film sizes are identical except for the spool. The 120 film spool is more robust. The width of this film averaged 61mm and the length 820 thru 850mm. This length provided 8 exposures format 2 ¼ X 3 ¼.

It is unlikely the negatives in your collection came from the same roll. I would think that you can look at the edge printing on the negatives to find the frame numbers.

One caveat – Some long roll cameras were in use. These were mainly used by School Yearbook makers (school photographers). They contracted to make portraits of all the students. They also took sports shots and group pictures and the like to include in the school yearbook.

These firms used long rolls 30 and 100 foot long rolls loaded into custom made cameras.
This is 120 or 620 film, likely 120. No difference except for the winding spool, 120 spool more robust. Both had edge printing applied via a light exposure. The edge printing, being an exposure, develops up with the image. The edge printing typically identifies the maker such as Kodak or Agfa etc. Additionally, the edge printing has an emulsion batch number and other similar codes.

At time of manufacture, it was unknown what model camera was to be used. Some models made 8 exposure wallet size negatives. Some models 12 exposure 6 by 6-centimeter square negatives. There was several models that made half- wallet size 16 exposures to the roll.

Most films were sent out to a local photofinisher. These were regional large photo labs that specialize in developing and printing hundreds of rolls a day. The problem was, when negatives were returned to the lab for reprinting or multiple prints to made, how to identify the targeted negatives? Edge printing to the rescue.

Now the fact that a roll could be exposed 8, 12, or 12 frames presents a problem. Which frame is # 6 which must be identified to fill the reprint order? If you look a the edge printing you will see duplicate frame numbers. To complicate this dilemma, the camera operator advanced the film via a number that appeared in a red window. These numbers were printed on a backing paper that wrapped and protected the roll from accidental light exposure. The camera operator was usually not adept at manually advancing film and often under of over advanced. In other words, identifying the frame number of the wanted negative was hit or miss.

I grew up in this business and as a kid, often pondered which frame is which. The V might mean this row of edge numbers is for cameras that were held vertically. I don’t know what the V is. But I know, the rolls of the mid 1949 were mainly 8, 12, or 16 exposure per roll, The 16 was half-wallet.