It didn't work out that way ...
>> Many NN0 codes were assigned as central office codes whenever and
>> wherever they were needed, without regard to their positions on Chart 5.
>> Examples that come to mind:
>> 702-870 (#3 on the list) ca. 1989 Las Vegas
>> 312-990 (#32 on the list) ca. 1988 Hinsdale
>> 201-460 (#36 on the list) ca. 1982 Lyndhurst
>> 414-730 (#52 on the list) ca. 1986 Appleton
>> 214-680 (#54 on the list) ca. 1983 Dallas
I was in Falmouth, Massachusetts in 1972 and they had a CO prefix
617-540 (KImball) now of course 508-540.