Colored dogs and muliple eyes

Could someone please explain the older RCA vinyl records with the different colored or shaded dogs (Little Nipper) and the various number of eye configurations on Columbia vinyl. Is there a huge difference in the fidelity of these various pressings, or is it the scarcity and collector premium that accounts for the price differences. Also, the sequence and years of issue, or do these styles overlap for the years of production. Thanks in advance to those analog buffs who are more knowledgeable than I am!