At Brooklyn Bethel and Watchtower Farms in the mid 70s, the issue was not beards, but moustaches!
I remember shortly after I started learning how to operate a Smyth Sewing machine (for books, not clothes!) in the Factory overhearing the floor overseer Gary Ellis tell a more experienced operator why he had been moved away from the view of the tours. (This brother was missing the attention of the young sisters who would come through on tour and now he was back by the windows overlooking the Manhattan Bridge instead.) Gary Ellis explained that since this brother was now sporting a moustache he could not be up and front for the tours to see as he was not "a good example"! I still remember the disbelief in this young brother as Gary explained this to him. At the time, I was a self-righteous no-good Bethelite and I thought Gary was doing the right thing. This would have been late 1973 and I think Brooklyn "liberalized" about moustaches soon afterwards, however.
But, not Watchtower Farms. In 1975, I was transferred to Watchtower Farms and I well remember what some of us white brothers called "The Moustache Rebellion." The Farm Overseer, Harlan Mathes, was dyed-in-the wool against facial hair above the lip. The only guys who were tolerated with moustaches were African-American and Hispanic brothers because it was supposedly okay in their culture. Still, one black brother named Kyle who was originally from Queens was grilled about his moustache. He told us about the questioning. "None of the Governing Body have moustaches," he was told. His reply: "Do you want me to jump into a bleach vat, too?!" (This was before Sam Herd was appointed to the GB.) They gave up on trying to convert Kyle to shave it off. Late Spring, a couple of the Farm brothers decided they'd test the waters on this and started growing moustaches. By this time, I'd gotten less "theocratic" and felt that this was an unnecessary restriction on our Christian freedom. I even joined in this mini-rebellion, but my change in appearance was not immediately visible as I was still young and my facial hair grew slowly. At the Farm, however, it was not a question of possibly stumbling tours of brothers (some of whom already had moustaches!), but there was the hint we might get the boot if we continued in opposing Brother Mathes. The ringleader of our rebellion was called into Mathes' office and he recanted and at the noon meal we saw him clean shaven. We all soon abandoned the cause.
A few months later, Mathes was replaced by Bob Lang, who was much more reasonable. I left the Farm soon thereafter, but I imagine the restriction on moustaches was relaxed before much longer.
In 1977, the best man at our wedding (in Eastern Oregon) was a Brooklyn Bethelite who sported a nice moustache. (Originally from our home area, he had grown it after arriving at Bethel.) My pioneer wife-to-be was stumbled when she saw it and asked him to shave it off in order to be in our wedding. (A mini-crisis the night before our wedding!) I defended him and his moustache and it still graces the pictures of our wedding day!