The above two scans of pages from the manuals can be viewed full size by clicking the pictures.
The carriage and knitleader parts will be the same for the KH891 as well.
The KK93 is virtually identical, but 2 differences come to mind that I am aware of: the KK93 has the builtin Intarsia
feature as well as Thread Lace capablility.
Also, note, the KH881 does not have a slotted back rail which prevents it from using the newer G-carriages. It must use
the older G-carraiges that come with a set of slooted railed to place over the existing rails on the bed of the machine.