Bernard,
I love the explanation of the acid stamping, but I am doubtful that a set would be stamped, kept together and then packed.
It doesn't stand up to my (admitted limited) experience of going around glass factory production where the different processes occurred within different sections. The bowls would go onto a stack, probably on a trolley, whilst the next was being stamped, then added to until they are wheeled onto the next process, or going into storage. Packing usually being seperate and the last process nearest the ditribution point.
I would have thought the matching bowls were more likely picked off the stock shelve seperately and it was a coincidence, but I guess different factories, different methods

I agree with the probable attribution of Walsh '
Pompeian', but thought that I could add nothing worthwhile to the first reply.
Nigel