Spark plugs (how to read them?)

89 Jeep Wrangler YJ 4.2 liter carbureted engine. Changing the plugs. So from what I remember (123&5) all look almost perfect. 4&5 may be signs of leaky valve seals (possibly oil in an atomized state?) Engine doesn't burn any oil that I've been able to tell and doesn't smoke blue.

[GLF]

#4 looks like either bad valve guides or valve seals allowing oil to pull through and atomize. #6 could be the same although a plug not seated can look like that.