I have a Toyota 4runner that uses standard peanut bulbs. You are correct in your assumption (at least in my case)
that the bulbs have a colored rubber filter. I switched my dash lighting from green to blue. I was able to find the same bulbs at the Chevy dealer, which were used in their truck dashboards to illuminate the high beam indicator. The high beam in my truck used a clear bulb to light a colored dash indicator.
Hope this helps.