Pop RiveTool Kit No.103 from 1964 by United Shoe Machinery Corporation (USM) looks to be complete in box. Box is in fair shape, pamplet is in vg shape, tool (PRG410)does not appear to have been used much if at all, and has more them 15 asorted rivets included . The Kit box is printed 1963 but the assorted rivet box is printed 1964.
It appears USM was the first in the '50's to build a machine to manufacture pop rivets in quantity and quality. Then other companys tried to copy the machine to produce the pop rivets through shady practices, they had USM blue prints and an younger engineer (Former USM) to copy the machine. USM sued in the '60's for stealing the design and won but it seems it was not until 1984 that the suit was finally settled. Very interesting internet reading.