Tiffini,
Sorry it has taken me a bit to get back to you!

I'm busy reading books for the new Boy and Girl 7/8 Book Packs for DITHR, and it is taking me so much time!
I see two options for credit as far as the history portion of Rev2Rev goes. With the time and level of resources in Rev2Rev with extensions, you could easily award a full credit for history. You could list it as American History 1490's-1880 or 1900 or so.

Or, if you were planning to do government, you could give a half credit for early Amrerican history and a half credit for government. Since government is partly covered within the time spent on early American history in Rev2Rev, the "time" spent on that area could either be counted under American history or government. If you added a lot for government, then you could potentially award a credit for early American history and a half a credit for government. This will depend on how much extra you add for government.
Blessings,
Carrie