Yes, the TBIs are normally that tarnished. If the fuel injectors are spraying good, don't replace them. The connectors are brittle, but still work when broke, and you can get replacements. Ask him when the plugs were changed and what plugs he put in it. If he put some silly Split-V-Ultra-Double-Fire-Plutonium plugs in it, junk 'em. If he used AC Delco, NGK, or even Autolite, and can remember when he installed them, I'd call it good.