This took some effort to track down so I figured I will share. (the suppliers carry ten of thousands of different PCB spacers and stand-offs in hundreds of configurations, and each supplier uses the same terminology differently... "spacer" and "standoff" may or may not mean the same thing.)
My Gottlieb System 80 Volcano (1981) uses this style of nylon stand-off to hold the circuit boards in place. After 40 years, some of the inner locking tabs are worn out, missing, or the whole mounting pin is just totally snapped off clean.
The size is measured as the air-gap between the surface of the wood and the underside of the PCB. They are all attached to the wood panel via a through-hole and a self-threading #6 screw with a slotted-flanged-hex-head, a.k.a. sheet-metal screw.
The sizes are as follows (for Volcano, likely similar on other System 80 machines)
• ⅞" for the various boards... MPU, PS, Driver, Sound, etc. (qty 22)
• ⅝" for the Credit display (qty 4)
• ½" for the four Score displays (qty 16)
Docent Electronics sells the ⅝" size (credit display) on their System 80A/80B and System 3 pages, but not any other sizes... I already asked.
I managed to find them all on Mouser. According to the data-sheets, all critical dimensions are the same including a 2.9 mm mounting hole for a #6 self-threading screw (3.5 mm O.D.). I have no idea if these are same brand originally used, but they appear to have come from the same molds.
¼", ⅜", ¾", 1", and ~1-⅛"