Dickinson's ingenuous argument doesn't address the claims about the authenticity of the above mask -although he demonstrates how difficult it would be for Schliemann to carry out the alleged fraud. Rather, he notes a telegram sent by S. whose contents are incompatible with the idea that NM624 was considered by him to be Agamemnon.
"“In the last tomb three bodies, one without ornaments. Have telegraphed to
Nauplia for a painter, to preserve the dead man with the round face [my
italics]. This one is very like the picture which my imagination formed of
Agamemnon long ago.”7 Surely, the “round-faced man” could refer only to NM 623."
NM 623, pictured above was also extensively described by S. in his book, and was associated with richer burial goods than NM 624, thus making it more likely that he would be the high king associated by S. with Agamemnon.
Of course, we now know that the Shaft Graves date several centuries before the Trojan War, so none of the buried individuals is really Agamemnon.
Link (pdf) Hesperia Volume 74, Number 3, October 2005.