Any ones with a bolt attachment will fit if you get rid of the base mounts as well.
There are heaps of cheap pillion pegs that will fit that way.
You can keep your possibly RIVCO passenger footboards with RIVCO adjustable fwd extensions and at least one other brand of extensions exist out there too. These allow the pillion's foot boot to easily clear panniers and provide a more comfortable position for most pillions.
Also I have found that if you remove the rear peg mount and the cover plate over the muffler hanger you can use the stock factory Touring rear passenger foot-boards that will mount to the rear exhaust mount bolt and the rear pillion peg bolt hole.
If using rear standard peg mounts extensions.
Rivco Product Code: TA005-5
$159.90
PASSENGER BOARD RELOCATION ARMS - AMERICA & SPEEDMASTER