I have never had a CEL with my 89 no matter what (weird), but I think for other reasons that it's a likely candidate for O2 and cat (and carburetor rebuild).
(For me the carb is probably first, planning on paying shop for it this fall. Biggest issue is loss of AAP functionality... something that probably applies to no one except
ooold 4A-F engines...)
I've had the exhaust manifold out and noticed a lot of white deposit on the O2 sensor... that plus likelihood it's original at 225k is my criteria for thinking it should be changed... on newer cars it may be worth a voltage check and/or code-scan as well... (but on the 4A-F my best guess is I should wait on the O2 until just before I send it out for the carb - don't want the new O2 getting deposits due to the old carb.)
More to the point, Scotty Kilmer had an episode on testing pressure fore and aft to diagnose a plugged cat. I might try this next spring, depending on many things between now and then.