Norelco was just a near straight copy of the Philips. I think Philips allowed free licence in order to ensure the success of their cassette based idea/products.
I'd still say that the EL3302 is the most likely model used. It has a dedicated speaker out and a small mono speaker, which matches what Keith has described, was available for it and shown in 1967 Philips brochures etc.
Interestingly, Stash recently auctioned off a Philips EL3302, saying it was given to him by Keith... perhaps this was
THE EL3302 used on SFM, JJF and PW.
I still have my EL3301A, but to be honest, other than for seeing if it got the sound, it's pretty useless as it has so much wobble.