You could likely adapt any number of different limbs to that riser.
You MAY be able to take a set of ILF limbs, remove the ILF fitting, and the hole would match up with the hole in the limb the fitting was in. Then, you just go to the hardware and get a 3/8" plastic grommet to put in the hole on the outside.
If that won't work, then you will likely have to drill an index hole in whatever limbs you decide to use. Also, to mae them match really well, you are going to have to knock of the corner it appears.