DaMoshe,
“There was an interview years ago with R’ Yosef Tendler zt”l, who was one of the early students of R’ Ahron Kotler in Lakewood. He was asked if the talmidim at that time wore black hats. He said that no, only the Rosh Yeshiva and Mashgiach did, and it would have been considered disrespectful for the boys to wear them.”
Can you point to a source for this interview? I find this difficult to accept as presented. First, in the 1940s when Rav Kotler started BMG, everyone wore hats, Jew and non-Jew alike. Black fedoras were extremely popular in the US. So it certainly wasn’t just the Rosh Yeshiva who would be wearing a hat. Second, I have seen photos of yeshivos from that era, and everyone was wearing hats. Sure, not all of them were black, but many were.
“How times have changed.”
It’s ironic how chareidim get dinged on both ends of this.