I just had a professional rigger inspect the lower parts and he said it is fine and does not need replacement.
I don't know how he could say it doesn't need replacement until he has inspected both ends. He was perhaps making an educated guess as to the condition of the upper fittings. It is more common for the lower fittings to go first, but I've seen the opposite a few times.
When I do an inspection and the owner tells me that the rigging is over 15 years old. I tell them, before I begin, that even if I don't find any obvious defects or problems, I'm still going to recommend a re-rig. This is based on the information that I get from the vendors that I buy my wire and fittings from. As well as personal experience.
I think that the fact that you made a post about it indicates you are somewhat wary and something is telling you that you should be concerned.
Imagine how that feeling will be amplified when you're miles off shore in rough seas and squall on the horizon.
Peace of mind is often worth a lot.
And don't forget the chainplates. They probably haven't been inspected, much less replaced either.