I'm starting to think the whole "HD exclusive" thing is just a misconception.
There is one new trick that we believe is HD exclusive, and that's the ledge+roll clip. It works because the mechanics of the roll have changed to always be the same speed/length (i.e. you can't do a short roll). This new technique allows for the new Earth Temple small key skip and the clip to get into Hookshot room.
The clip at Helmaroc could work differently. In fact it feels different than the others. You don't roll right away out of climbing up the ledge, you run for a bit and then roll. Is the clip performed the exact same way on SD? If so then this may not be an instance of the new ledge+roll clip and could just be a brand new skip that works in both versions. But as far as we know, the ledge+roll clip is not possible in SD, so we call any skips that utilize that technique HD-exclusive.