Kodagraph was the generic trade name for a series of extreme contrast photo-drawing materials, both negative and autopositive, that Kodak once made. According to their 1952 booklet, both Dektol and Kodagraph developers were recommended for those materials, interchangeably. The booklet says nothing about the differences between the two. My guess is that the Kodagraph develope may favor high contrast materials in some way. If you're adventurous, you could try it on some prints. Remember that it is very old.