Replacing an odd dial lamp

[YamahaFreak]

I have a Lafayette 99-5014 tube-based audio frequency generator that works well except for its burned out pilot light. I have had no luck finding a replacement. The bulb is a metal tube with a red lens at one end and two terminals at the other, and is permanently sealed. It mounts flush to the front panel and secures with a nut from behind. Supply voltage is 97.5 AC according to my meter. I'm assuming it's got to be a tiny filament bulb? The only markings on it anywhere are the words 'JOSIN' and 'JAPAN' on the bottom around the terminals. I have attached a photo of the lamp for reference.