Hi Andrew,
The most significant difference between the H-1-c and H-1-d was the pilot.
The H-1-c's had that older 'V' shaped pilot found on the F-1-a's and the H-1-
d's had the smoother wrap around style like on the H-1-e's.
2859 ended up with an H-1-c pilot and one of the H-1-c's ended up with
2859's. I can't rememer which one exactly. It may have been 2838 or 2846.
cheers,
Andy Malette