It has nothing to do with the pressing inside (so #4 doesn't mean fourth pressing!)I would like to compliment you on the interview with Phill (with two l's).Central plating generated the mothers that the plants would then pull stampers from.At Warners they bought Sheffield Plating which did plating for all the plants.” The system may have been different for mono or different during the ‘60’s because I received this image from either Sundazed or Sterling Sound when the mono Dylan titles were mastered: It shows but a single lacquer sent to each plant and the 1A going to Terre Haute.
I have a -3 so I can be sure about that, I don’t have a -2 so I can only speculate about what was changed there.Perhaps by then mono was in decline and a single lacquer sufficed, but it doesn't explain why the 1A went to Indiana.These symbols, often found in the inner groove area identify Columbia Records pressing plants: CT or CTH = Columbia, Terra Haute, IN CP = Columbia (Pitman, NJ) CS or CSM = Columbia (Santa Maria) Incidentally the number found on the back jacket, right hand lower corner of all or most vintage Columbia jackets refers to the jacket manufacturer.We would sometimes at Columbia and later almost always at Warners have one plant do the plating for everybody. At Columbia it was almost always Santa Maria because they had the newest-and best-plating operation.
The masters would still carry the dash number for the plant doing the pressing.It could have been the “From a Buick Six” change and perhaps -3 has yet another change that I’m not aware of.