This is the classic Leatherman tool, first available in 1983. The example pictured is a fairly early example (c.1986) manufactured in Japan. At that time, with demand greater than Leatherman’s facility in Portland, Oregon could keep up with, the production of Leatherman’s only two tools at the time (the PST and the Mini Tool) was partially subcontracted to Mitsuboshi Cutlery for a few years, resulting in some PSTs being stamped “Japan” on the blade tang.
PSTs with riveted construction as pictured are quite sought after by collectors, and show many different “random” characteristics.
I’ve accumulated a few of these by now, but have no idea how many variations I’ve still to find – even Tim Leatherman himself isn’t too sure, having commented that both in Japan and Portland, PSTs were stamped and assembled in any way necessary to get them out of the door!
There’s a great discussion here at multitool.org about the PST – a must read for PST owners!