A forgery isn't a subjective assessment. A forgery is intentionally made inaccurate claim of the origin of something. If the by-line is claiming it was made by

A forgery isn't a subjective assessment. A forgery is intentionally made inaccurate claim of the origin of something. If the by-line is claiming it was made by someone who didn't make it, it's a forgery no matter how good of a copy it is judged to be.