Obviously age isn't the relevant factor here, condition is. If they're clean and true and not rusting out and well maintained, you'll be fine.
If you're missing spokes and the nipples are seized and poorly tensioned and the rim is only a vague approximation of a circle, then you should be more careful.
Not to mention that a 30 year old 36 spoke touring wheelset is going to be stronger than a modern 28 spoke road wheelset anyways, if both in good condition. Aero rims are stronger than box but the number of spokes makes a huge difference.