If the shifter still works, I wouldn't bother. There are a lot of tiny bits in the shifter to mess about with.

Who needs the indicator anyhow? It's just a "nice to have" feature in today's shifters. God knows how folks did it back in the day of thumbie friction shifters. Oh wait... you just rode and shifted when you needed to. You don't need an indicator to tell you which gear you're in. When gear indicators get to road shifters I will have lost faith in humanity...