I thought I knew brakes, but apparently not. I ordered reman Ate calipers. One caliper is stamped "Bendix" but has the short bleeder, sheet metal clip, no ears for the wire clip, and barrel spring slide pin retention. Basically these are Bendix calipers that look like Ate calipers. Does Bendix just make Ate style calipers these days?
Where did you get them? If one is physically different from the other, I think I'd be looking to return them and try again. What's the application?
Edit: A quick search reveals a good bit of discussion on the topic. The quick take seems to be that either will bolt up, but you should not mix them on the same axle. Also, pads may be different. All the discussions I found concern Mercedes Benz vehicles. For example:
https://www.benzworld.org/threads/ate-or-bendix-calipers.1341139/