Always fun to go to the source and read. Here's a catalog from 1923 that shows you all the options for the #7 outfit. #7 is probably not a number 2. #7 is common. It could go up to 8X10 but film costs after WWII made most studios switch to 5X7 backs later on.
There may be other lenses on seperate boards for this outfit. Most studio's had different lenses for different types of jobs. The Wollensak Velostigmat Series II f4.5 12" was in production for many many years. This catalog from the same time frame shows the Wollensak lens you're describing. Look at it closer next time and see if the numbers 0 - 5 appear near the front rim for a diffusion control effect that was possible.
Finally, if you're bored and have time on your hands, look at my web pages for hundreds of images done with just such a camera as the one your friend had. They were made to be USED! Tabletops and portraits are what they lend themselves to best.
some of my cameras and lenses