Is this an Altec Woofer?

[Storm]

I finally decided to take a peak inside the cabinet of one of my Altec 846U speakers.

After 6 screws on the horn and 16 on the woofer...here is what i've got.

The horn is an 811B with an 806A driver - 8 ohms.

However, the woofer appears to not be Altec - not sure. The magnet is labeled as such, but I have not seen an Altec basket like this one. Is it an Alnico??

Can anyone verify?

All of the serial numbers are 3915...both inside and outside of the cabinets, so I am guessing - 1975?

Has anyone figured out the serial number and dating codes for Altec, yet?

Thank you.