Need Help Identifying the Driver

Bought this used 10" driver. The sticker says "K10" so assumed it was a Celestion. The magnet with the vents seems typical but the dust cap is concave. The surround has a single roll whereas in pictures the K10 has two. Also the K10 has a pressed steel basket and this basket is cast.

Any ideas?

Celestion K10b.jpg
Celestion K10a.jpg