I bought a manual for a piece of test equipment I had that was  used in crystal production,  purchased from Tucker's as they were shutting down.  In the manual was a typewritten set of instructions by the Midland Company, yes the CB maker, that was detailed in how to make sure the crystals being ground were being ground properly to freq, how to test them and fine tune them.  Midland made all their radio  crystal in house, and these were the metal holders like HC6 where the leads were attached directly to the crystal itself, so I am thinking that while the process is labor intensive, by the 60's there was a lot of automation to it making it a bit less labor intensive, and something a company did not farm out..

Charlie, W4MEC in NC