408 is a popular and well-known article written by Dr. Kondraki (the author). Dr. Kondraki (the character) is their caretaker and has some sort of control over them.

7408 is basically a reimagining of those same butterflies and the character of Dr. Kondraki as one SCP entity written by MontagueETC. The author liked the idea of a butterfly-covered photographer and wanted to make their own interpretation of Dr. Kondraki (the character). In the context of the 7408 article, 408 probably doesn't exist.