If it's just an "H" it probably refers to a level line (they were inexpensive and popular back in the day).
The "H" would be a 2 weight. This is pretty light for an old rod, but at 7 feet it certainly could be. If you can, try casting a borrowed modern 2 weight line on it to try it out to see how it loads the rod. If you have a buddy that has a 2 weight line that would be perfect, if not, if there's a fly shop near you and you could try it out before you buy, that would be great. The reason I'm suggesting this is because 2 weights were fairly uncommon compared to 6 weights for example. Does it seem like it could be a 2 weight?
In a double taper 6 weight for example, the old school designation would be HDH, where the thin diameter part of the taper at either end of the line would be diameter "H", and the belly of the line would be the thicker diameter "D". So if there's a chance any of the letters got rubbed off it might look like an "H" (modern 2 weight) when it's really something else.
If you have any other fly lines like a 5 or 6 weight for other rods, you could try them on the rod, (take it easy on the blank) and see if it seems like the line is way heavy. If so, then it's more than likely a 2 weight.
If all else fails, the folks at fiberglassflyrodders - Message Board - Yuku
could probably help you out, or you could contact Wright McGill.
Hope this helps. Sounds like a great piece of history you have there. It'll be great to get it out on the water. Good luck with it!