I'd be surprised if there were a factory option since original purchasers would probably have just bought one or the other depending on their needs.
In this case it looks like you could buy a used or replacement crosslide from anything that looks suitable and adapt it. Adaptation means a flat slab that has the four bolts to go in the slots, probably a close fitting hole for the spud on the crosslide and either a fiducial mark or degree graduations depending on your choice of crosslide.