I don't recall any bulbs, but I dont have it in front of me, or use it often.
One thing I just noted in an old Omega/Essco analyser that came my way last week, was dim bulbs on some indicators. It turned out after disassembly that the bulbs were #47 neon indicators bulbs, with a mask to let light out the front only, and then a coloured rubber sleeve over all of that. The cyan and magenta dyes in the different rubber sleeves had darkened, so that barely any glow escaped.
I took the darkened rubber sleeve off, and taped a couple of layers of theatrical gel of the right hue from an old Lee sample swatch book over the back of the window hole the light normally was viewed through, and now the bulbs function can be seen again.