I had 2 x 12's from a fender twin which were allegedly Eminence, not sure the model. They were in an open back cab a friend had as the top end of his bass rig. I still have one, the other fried because my B200s (a very early model) went lala on one channel. I used them for years with a 1972 Marshall 50w and later with my first MP1 rig (MP1 > Alesis Quadverb > B200s), they were great speakers.
If those were the blue labelled Fender Special Design speakers they used throughout the 1980s and early `90s, they were a version of the Eminence Legend with a heavy magnet and large speaker coil, made specifically for Fender to handle the 160W Pro and London 185. I have the exact specs on my home computer (I`m not home at the moment). They used them in the Twin and other amps also. I looked into it years ago and was told that directly by Eminence.
I have a pair from an open back Fender 2x12 cab, myself, and I have to say they are perhaps the best sounding speakers I`ve ever heard in that application. I`ve tried other speakers in there thinking I was upgrading (I have Jensen C12K`s in that 2x12 now) but those Fender-Eminences are honestly the best I`ve played. They`re fat, clear, sweet, expressive, sensitive... just a damn fine speaker for an open back 2x12.
It`s probably human nature to think the grass is always greener on the other side, and that the stock speakers can`t be that great (especially when they were so common), but those really were.