It's obviously a custom gauge, as the bottom of the gauge has lettering on it saying "World Wide Fiero Club". It can be pretty much surmised that it didn't come from the factory that way.World Wide Fiero Club
was a Fiero car club, that used to put out a newsletter, "Fiero Secrets" that covered all sorts of Fiero related topics and repair instructions.
Also, from doing all of the Fiero Reproduction Stickers and working with TONS of Fiero fonts, the one on the 150MPH speedometer does not match any of the Fiero fonts that I have come across. Have a look at the "2" on the speedometer, and the "2" on the Tachometer, they are entirely different. 99% of the time, all the gauges in a particular car use the same exact fonts throughout all of the gauges. You can clearly see two entirely different fonts on the Speedometer and the tachometer.
[This message has been edited by JohnWPB (edited 09-15-2014).]