I could "play along" with the songs on the banjo(I know some chords on a banjo) and also with my B-flat accordion after slow down the music of course.
But with those giants you're never sure if they really play on that accordion, because they can play those songs in more than one key on any accordion.
For me it's like, I never know for sure :-)

With most creole zydeco players....they play on the pull in the 5th key for almost every song in the entire zydeco genre. So yeah,
if its a Bb accordion, they plsy in the 5th key which is "F".
If its an A accordion, they play in the 5th key which is "E".

But us white folks ain't supposed to know that, so shhhhhhhh.