Linseed oil used to be a popular item too as are good quality furniture paste waxes.
Kinda fell off over the years, and even moreso once stuff started going all polymer/carbon/fiberglass instead of good quality wood.
In any event, if it was never sealed with shellac, varnish, eurothane or the like, I wouldn't do so now just to 'update' it as the probability is high that you might get a good pretty finish on it of a gloss/matte level of your choice, but you'll also see cracks start to appear as the wood that was kept for so long with oils or waxes suddenly starts to dry up, shrink and deform after things are made more or less air tight. (moreso if the whole part is dipped as opposed to inner unseen points being left bare)
Its kinda like trying to shrink wrap a cracker for want of a better analogy.
'Course if you put brand new previously untreated furniture on that wouldn't be an issue, but on older cured stuff its askign for trouble.