Howdy!

If you're talking about the Judges Guild product, it is indeed the original Blackmoor campaign. The product is a book containing additional pre-AD&D rules to use with the original boxed set and various notes from Dave Arneson about the original campaign he ran, and a

DM's and Player's map in the format of the

JG Wilderness map sets, but on the scale of 10 miles per hex instead of 5 miles.

Hope this helps.