Yep - that's exactly what they are and will also fit some M & MC models. I have a pair of MC120.2's mounted on these. Luckily you also have the pegs which screw into the back of the speakers.
I can't tell which model speakers they fit though as I think the hole centres differ between some models. Quite a rare item too!
EDIT - just checked my brackets and I'd say the ones you have are for the smaller in the range such as the S35/45 etc... as mine appear to be bigger - the pegs on mine also seem a bit longer. Just a guess though but if you can tell me the distance between the hole centres (between the left & right slotted holes as your picture sits) I should be able to confirm a bit more. The hole centres on mine are approx 180mm.
Chris.
The use of metaphors should be avoided like the plague. They're like a red rag to a bull to me.