One little tidbit about the regular Grappler Plus: more recent versions had a 374 at U10

Quote
https://support.apple.com/kb/TA36748?locale=en_US

Apple IIGS: Grappler Plus cards
This article has been archived and is no longer updated by Apple.

Older Grappler Plus cards are not necessarily Apple IIGS compatible. Some of
the older interface cards malfunction because of timing changes made to the
IIGS slots, even though these changes were within Apple's specifications. The
Grappler Plus card was designed before Apple even had those timing
specifications.

On the Grappler Plus card at location U10, if the chip there is a 74LS373,
then you have an old card and should contact Orange Micro. A 74LS374 is at
U10 on the recent card.