Joke's still really funny even if it's wrong, but yeah, from his My Room lines, Muramasa still cooks.

If I translate his my room line right

Fun fact:His personality instead of being old man Muramasa it is old man Shirou,Personality of Shirou that live until get old

asura007 said:

If I translate his my room line right

Fun fact:His personality instead of being old man Muramasa it is old man Shirou,Personality of Shirou that live until get old

From another translation that i found in the sub-reddit of F/GO, it says that the personalities of "Old Man Shirou" and Muramasa are pretty much the same. So, at this point, is pretty much close enough.