01 kenworth dash light replacement??

hi everyone, i own a 2001 t800 tri axle. some of my dash light indicators are out. not all of them, so i know its not a fuse etc.. question is, are there small bulbs inside these indicators? i know 2002 and up are a bulb that pops out. but how about the older ones.. can i swap bulbs or do you buy new indicators for the ones tht are burnt? been bothering me and i cant seem to figure out my answer