First off its hard to find brake hardware for the Bendix calipers and it seems that ATE hardware is more abundant.
I have Bendix calipers on my 85 300TD and it seems to me that the Bendix calipers are being phased out. As long as you have the same on the front or the same on the rear all is OK. You just don't want A Bendix on the left or right and an ATE on the opposite side.
But front to rear different calipers is OK.