Here's what rear axles where available in 1992. Looks like Canada did not have them.
ABS, 2.73 ratio
ABS, 3.08 ratio
ABS, 3.55 ratio
ABS, 4.10 ratio
w/o ABS; (Canada market), 2.73 ratio
w/o ABS; (Canada market), 3.08 ratio
w/o ABS; (Canada market), 3.55 ratio
w/o ABS; (Canada market), 4.10 ratio
Here's what rear axles where available in 1996. Looks like Canada still did not have it.
ABS, 2.73 ratio
ABS, 3.08 ratio
ABS, 3.31 ratio
ABS, 3.55 ratio
w/o ABS; (Canada market), 2.73 ratio
w/o ABS; (Canada market), 3.08 ratio
w/o ABS; (Canada market), 3.31 ratio
w/o ABS; (Canada market), 3.55 ratio
I believe you are correct, they went to metric in 1997 except the f250hd/350 which stayed the same till 1999.