So far here's what I've found.

It appears that bytes 1 & 2 are the "header". byte 3 is either 01 or 09 depending on .GHO or .GHS.
Byte 4 appears to be a version indicator or some sort although I don't have any older versions of ghost so I can't verify. If you have versions of ghost other than solution suite and 8 please pop the file in a hex editor, or run
dd if=/path/to/file bs=64 count=1 | xxd
to get the first 64 bytes of the file.

Byte 5 is the Ghost file index indicator. Basically it's randomly generated but the .GHO will be the lowest number, and each .GHS will increment by 1. Bytes 5-8 are a unique identifier for the ghost image and they are consistent across each file in the entire image.

To illustrate these findings:
file1.GHO
FE EF 01 03 D3 CC 12 43
file1-1.GHS
FE EF 09 03 D4 CC 12 43
file 1-2.GHS
FE EF 09 03 D5 CC 12 43
file 1-3 .GHS
FE EF 09 03 D6 CC 12 43