VIntage & I have been talking about these via PM's. They are clearly AR woofers. The question is are they original 3a woofers. The dust caps don't look original to me, but replacements from when they were refoamed. There's woofer images in the AR3a restoration guide, though not all show the magnets.
There's a thread on the CSP site about AR9's, and Roy C. mentions the 9's woofers with a pic, that shows the same magnet as shown in the above pics. It would be helpful to see the top of the magnets to see what numbers are stamped on them.
I restored a set of 3a's last spring. One had a service replacement woofer, also used for the AR9 among others. I could not hear any difference in sound between them. I asked Roy about it and he told me they all pretty much sound the same.
Looking forward to what others opinions are.