No one may still be reading this thread, but in case they do,
yes, James Cagney (who didn't like being called "Jimmy" - a diminutive used against his wishes by Warner Bros for marketing - he much
preferred plain "Jim")was an accomplished guitarist, and there are a number of surviving photos of him playing guitar (and at least one playing ukulele!)...at home, on various sets,
even off-set in Hawai'i. I believe his Gibson guitar was sold
at auction (Doyle) after his death. His training was classical. The real
Cagney was very unlike his screen gangster persona...a talented amateur painter, cook, horseman, poet, and definitely much more than an
amateur musician. (A lot of piano-playing photos survive as well. Heard he played the drums, too.)