I have a Letter from the early '70's, somewhere in my Files, from Bethel on the matter, it is the usual mealy mouthed stuff, but even back then they said that in certain parts of the World and Cultures it was acceptable.
But they said it would be up to the Elders to decide if they appointed someone with a Beard, to a "position of responsibility". Of course you were as usual subject to the prejudices of local Elders.
I grew a beard shortly after receiving that letter, I was an M.S. at the time, nothing was said by the Elders, which was strange because a few month earlier I had been "counselled" about the length of my sideburns ! yet, let that develop in to a full beard and they say nothing ??
I served for nearly 20 years with a beard, and used to give "Away" Public talks at the time, it was made plain to me that I would never be used on the Platform at a Convention, even for something like a F.S "experience", and yet in later years, after my beard was shaved off actually, they used a lovely old boy in an experience at our Circuit Convention, wearing his rather scruffy beard, so were obviously more relaxed then.
When I was told you could not go on the Platform with one, I asked to see it in writing, and the bro I was talking to whipped out the Instructions for Handling Assembly Parts or whatever it was called, and there it was, by the Org, with very doubtful Scriptures to back it up, and faulty reasoning too, "People may think you are an Anarchist" or similar. In my Culture at the time, in the U.K, the only people wearing beards were generally Professional guys, and Academics, so that being in those Instructions went against the letter that I had on File, but, I didn't care, I didn't want to go on a Convention Part anyway.