Sounds like you have got a pair of shocks for a Honda.....The best would be to sell them, and by a correct pair with the cash.
If you really, really want to use them, and if the forked end is not too wide, then a spacer inside the "fork", and a floating bushing through the fork and spacer, then the whole assembly inside the mount on the XS swing arm may work. (Assuming the lower end has the forked attachment)