Anders,
I have '6223 cranks with the '6223 and 3856223 part designations.
I have '7115 cranks with the '7115 and '71 part designations.
Honestly, the width of the counterweights on your '7115 crank has me confused
You may wish to expand this thread over on the NCRS.ORG site
as those guys can tell you for sure. Please keep us posted
in you learn more.
Steve