Stewart Warner Gauge Light Bulbs

[barely adequate]

This seems like it should be obvious, but I couldn't find any info on the Stewart Warner website. How do you go about changing the bulbs on the original (I think) Stewart Warner gauges found on a 1977 E27? Three of mine are out. There is a little black plastic sleeve on the back, but I'm not sure if it is supposed to just pop off or if it is threaded. Hesitant to apply pressure without more info at risk of breaking the plastic. Also, if anyone happens to know what type of bulbs they take, that would be handy!

 

[toddster]

Sorry, my old ones were "teleflex," brand, which pull straight out. If they rotate freely, they probably pull straight out. Bayonette-Style will only rotate a quarter turn (then pull out.)