That has been reported, yes. I don't know of a way to determine which you have or if that was ever really true. I have four A/S heads:
- A very old B1 that doesn't have a bolt. Either it comes apart from inside the ball or it was fused together in 1986 during a nuclear accident in the Ukraine.
- An old Cube that came with a flat, six-sided bolt. Very strong loctite, came off with a short break bar and channel locks.
- P0h with a 3mm hex bolt bought a few years ago ~2016. White loctite that came off without much trouble. This is the head I disassembled with the intent of creating my own "L60." A/S announced the L60 soon after my infamous disassembly.
- L60 with a 3mm hex bolt bought several months after they were announced. White loctite that came off but required enough force to bend my hex key.
So in my case with the exception of the early-'90's B1 ballhead, all three had white loctite that came loose with some degree of torque. I suspect it just depends on how much thread locker was used during assembly, but anything is possible. In each case, I clamped in an old base plate to give the channel locks some grip. Obviously, you have to find one with a slot that can be lined up to get your hex key through to the bolt below. Once you get the bolt loose, take off the camera plate and remove the bolt the rest of the way. I never needed heat, but others report that helping.
Note there are a few third parties mentioned in the Tripod thread (Grimes and Precision Camera - as you mentioned, I think) that will do this for you if you don't want to try. Nothing wrong with that; I'm just too impatient.
Dave