They are both Denso. Ford used them on some models mostly diesel vans. The ford had three bolts one on top being a pita

 

I know that we have denso-style IDI starters(and they work nicely if the brushes are in good shape). However, they are a serious PITA to install due to how the offset motor is positioned, like you said.

This other starter I found(the subject of this topic), which was labeled "Cummins ####" was a two-bolt design, fit, and had the motor rotated such that the top bolt was easy as pie to get to. It also doesn't impact anything.

If I ever buy a new starter, I'm going to try to find one of these two-bolt denso units, because they are so much easier to install/remove, and it looks like the extra bolt isn't needed.

I may not be buying a new starter for years, though, if all I have to do is solder in some new brushes.
edit: http://www.ebay.com/itm/NEW-Case-***...-/130923774661 might be like the one I found? (Edit: as far as I can tell, it should be the same or close enough... and it's a 2.5KW unit as well)