Reporting question for Knob - Ampeg, Classic, D Shaft with indicator line

Product:
Knob - Ampeg, Classic, D Shaft with indicator line

Question:
Will this properly fit the Transformer Balance knob on the rear panel of an Ampeg SVT 3 Pro? It is a D shaft pot which is slightly smaller than the midrange selector knob on the front panel. Nobody makes a replacement knob for the rear pot! Yet, in the manual and pics online, you can see the rear knob looks just like the metal knobs on the front.