Had 100k on it when you got it, but you do not know if it was ever apart, right? If it was me, I would remove it, take it apart for inspection etc. If all orig, it is WAY overdue for valve stem seals and other wear items, timing chain etc. Cool thing is date of mfg is usually on rod and main bearings, gives you an idea if ever rebuilt and all. If the bores are close enough to re-use, maybe just re-ring and replace freeze plugs, cam bearings and whatever else looks bad. The problem with stem seals is the way they love to become brittle, crack apart and find their way to oil pick up screen. And that would cause you expensive grief when out motoring around one day. Hopefully the timing chain is steel based cam gear that won't fall apart and also jam up pick up screen like the older ones.