It seems to be a measuring delema. Mounting holes are 3 1/4 center to center. Fork is 15/16 long from latch base. Lock assembly is 3/4 inch wide over plastic housing, and 4 13/16 Inch overall.
Lauren from SWISCO responded:
August 10, 2022
Hello, thank you for posting,
Please start by reviewing the style and dimensions of the 38-177 multi-point lock and 38-178 cover/handle. Let us know what you think and if you have any additional questions.