If it doesn’t fit the description ie has the features of a known production dial, then it’s a service dial.
Service dials were ordered in small batches often with non standard markings AFTER 321 production ended.
This at first glance seems to be a late 80’s era or later dial with someone attempting to faux age it. Unless I am misreading the “Speedmaster” font used.
AML might have been added later.