On show #1207, Oliver from CA called about a missing bolt after replacing the head gasket on his 1994 Toyota Pickup. On the 22RE 4 cylinder engine there is a hidden bolt on the front the head. Its underneath the cam gear and is usually hidden under a small puddle of oil. Its possible that’s where the bolt goes, though I would expect some oil leakage from the very front the of the head without this bolt. Do not silicone this bolt or the hole. The tolerance is very small and you risk cracking the aluminum head.
Also, the timing chain should have been done while everything was apart, including replacing the driver side chain guide with a metal backed aftermarket guide. The timing chain stretching out and wearing a hole into the water pump housing, and the nylon chain guides are the weak points in these engines.