Yeah, they are, I have a picture of the front and rears off my S5 next to each other somewhere, I'll try to dig it up. I'm pretty sure the S4s are the same size though. When I got mine from CorkSport years ago they were from D.SPEED/Japan and both sets were marked "Front Side". I actually had to trim out the mount holes a bit to get the rears to fit...
It would be great if you could get these made again, I get asked about mine all the time!
Edit: Can't find the pic I wanted but did find these...
