Well thats up to you really, i wouldnt personally?

The only things involved with your fault are, the alternator, the blue wire running to the instrument panel, the bulb itself and thats about it.

It would also be worthwhile whipping the instrument panel out, and giving the bulb a wiggle as the circuit on the back gets dirty after the years, might be a bad connection on there.

Its going to be something simple, its also VERY easy to remove the brush pack off the alternator and check to see how worn they are (probably getting worn), if your going to do that though for gods sake disconnect the battery first