Sort of.
The M13 marked were to be used with the M13 US link.
The carrier was marked but that part didn't really matter.
The sprocket and the bolthead are what matter.
HK made 3 sprockets and 3 BH's.
What setup you have determines what link you can run.
I made the MM21E run both by using a combo of the 3 styles.
All 21"E"'s are the same minus the above mentioned parts.
Thanks,Mike
MM