There were two different versions of Dunlop front calipers. I can find no information to indicate exactly what the differences were, but it appears that the difference is in the wheel cylinder(s). The factory parts book, Edition D indicates that there were two different types of brake pads for the Dunlop front calipers. I can't say for sure, but it seems reasonable to assume that one type of pads is for the early version of caliper, and the other type pads were for the later version of the caliper.

One indication of the time frame in which the change in the caliper occurred is the fact that the change isn't mentioned until the Edition D version of the parts book, after the changeover to the Teves (ATE) calipers. This may mean that the later style of Dunlop caliper was never actually used in production, but was used solely as a replacement part for repairs. I mention this to help address the unlikely situation where an owner buys a new pair of pads for his/her car but the pads don't fit correctly.

Dunlop brake calipers (of either version) where installed on the front brakes of the 300SEs through VIN number 112.xxx-xx-005866 after which Teves (ATE) calipers where installed.

The information on the rear axle calipers is a bit less clear. Judging from the information in the factory parts books, Dunlop Calipers were used throughout production, though there were three different versions.

Version 1 was used up through VIN # 006975.

Version 2 was used from VIN # 006976 through 008288.

Version 3 was used from VIN # 008289 to the end of production. (See End of Life/Break in Production)

The caliper version #1's part number is superceded by caliper version #3's part number but also requires replacing the steel brake fluid lines to the calipers. 

The caliper version #2's part number is also superceded by caliper version #3's part number but also requires a different set of brake pads. Interestingly enough, the pads are indicated to be those used for the front brakes with Teves (ATE) calipers. This almost has to be an error in the part number in the book. It doesn't make any sense to change to the later style caliper but not use the same pads as would have been used when the later style caliper was installed during production. There were no changes to the rotor anywhere during production.