Tire Matching

One of my studded 255/70/R16 T111 Nokian Hakkapeliitta tires picked up a bolt near the outside edge of the tread (near the side wall). Should I be concerned about running this tire for fear of a blowout? The tires are 9 years old and I can’t locate a exact model match. Can I replace it with another 255/70/R16 studded tire or do all 4 tires on my AWD Expedition need to be exactly the same? Would having identiacal tires on the same axel be sufficient?

After 9 years, I would be replacing the tires out of principle. They are likely dry rotted. Also your Expedition is not AWD, it’s 4WD. The Control-Trac or whatever they all it is not a true AWD system.