Yes, I was very much a JW during those times - baptised in 1972 after having been a regular reader of WTS literature for six years beforehand. Not only the congregation I was in, but all others I knew about as well (without exception), swallowed that one about 1975.
One of the more prominent elders in that congregation made no secret of what he thought about 1975; as late as May of that year, he was still insistent that the current set of tyres on his car was going to "see the system out".
Nobody in that congregation had an educational level greater than Grade 12. Furthermore, I am only aware of one person in the entire circuit who had a university degree (he was a geologist). The few who bucked the trend did no better than a Diploma of Education (qualifying them to teach school at primary level), and they were widely regarded as being over educated! Even those of us who actually got to complete Grade 12 were few and far between - to say nothing of being on the verge of that very disapproved of state of affairs, over educated!"
Your observations about the connection between education levels and skepticism about WTS chronology seem pretty accurate to me! The congregation you describe, though, seems a little different to most, in having a larger number of university graduates amongst its ranks.
In all the congregations I ever associated with, over 28 years and in three different countries, there was only one that a number of degree-qualified persons. This was an English speaking congregation in the capital city of a recently independent Third World country. As a consequence, its territory included the local elite, plus expatriate professionals who had remained behind on short, fixed-term contracts.
Apart from that, in all the other congregations I ever associated with, you struggled to find anybody who even held a diploma. I can recall one brother who was a Quantity Surveyor, and several who were school teachers. That was it, though!