The standardization certainly existed, but it was by no means total. I don't remember anything about pens on desktops, for example.
Rate plans certainly varied all over the place. Message rate service was the only service offering in many places; but in most places it was optional and flat rate service was chosen by a very large majority of customers.
After the breakup in 1984, the Bell operating companies were in a stampede to find other suppliers that Western Electric. W.E. was in the unfamiliar position of having to compete for business, and other manufacturers got a lot of the Bell business, including C.O. gear and outside plant.
Carrier technology was pretty common across many telephone companies, with many circuits and systems jointly owned with the independent companies owning the pnysical plant and terminal gear in its territory and the Bell company the same in its territory. Compatible gear was available from numerous independent suppliers.
W.E. gear, usually made to specs furnished by Bell Labs, was designed with the idea it would be in place for many years and was built to extremely high standards. This was particularly true of customer premises equipment, where the local telco provided all the maintenance -- on-premises maintenance. The cost of a repair call, whether for a simple telephone set or a massive centrex or PBX, was high, and it made sense to build the equipment to last. When customers were permitted and then required to buy and maintain their own equipment, this no longer made sense, particular for such simple gear such as a telephone set.
An effect of this in rapidly growing areas was the the independents, frequently bought up by GTE, owned the areas of high-growth, high-income in the suburbs. Some of this places where this was particular noticeable was in the Southern California area (General of California was larger than at least a couple of the Bell operating companies and attracted some senior Bell executives to fill high-level vacancies), Dallas (Irving, Las Colinas where many corporate headquarters are located, Plano, much of Carrolton and numerous others). In the Tulsa area, General, later GTE, owned the Broken Arrow exchange which served not only the growing and high-dollar limits of its namesake city but also well into the adjoining similar territory in the municipal limits of Tulsa. (As an aside, Bell speakers at the national level were wont to extol the virtues of a single nationwide long distance network by noting that you could reach even such remote places as Broken Arrow, Oklahoma, which always made us in Oklahoma snicker because it was about as non-remote a place as anywhere in the country. They probably meant Broken Bow, a place that would more or less fit the "remote" description and was served by a well run, locally-owned, non-GTE independent.)
Wes Leatherock snipped-for-privacy@aol.com snipped-for-privacy@yahoo.com