I ran a pair of the mono-block FP-11s for a little over a decade, and loved them. The FP-32 was "the" ENG mixer of the 1980s, and the FP-32A followed, later replaced with the FP-33.

When the guys that started Sound Devices left Shure Brothers, they landed the OEM deal with their former employers to replace the FP-11 with the FP-23 (Shure branded version of the MP-1), as well as take over production of the FP-33, which is still sold by Shure.

It's very easy to distinguish the later version made by Sound Devices for Shure. On the left side panel where the inputs are, it has "Made in USA" stamped on it instead of "Made in Japan". Also, the three main gain pots have the distictive look of the pots SD uses on their mixers. If the one you are looking at has these features, then it's the Sound Devices built version and well worth it.

Hope this helps.