I admit, I don't know too much about mud, and I have gathered up probably about 100 different porcelain pieces over the process of buying glass in bulk over time. I would appreciate any help in identifying this group by the U- # I think I have marked the one on the right as U-1352 as it looks like the picture I matched on a site and a previous sales posting by another member, it also has the letter U on the dome in the center, with the very center unglazed.

from the left, the big one has a B in a circle on the skirt (side showing the next 2 don't have any markings that I can see the 4th one says PP/Inc/1952 on the dome

any help with what U #'s and if they are of any value is greatly appreciated.