I’m pretty sure about this, but I also assume someone must have already said this in print somewhere? Maybe Russo? I’ve not found looked too hard yet, just throwing this post up because aha! moments are fun even if they are not actually new observations. Also this isn’t hugely unexpected we already knew the two issues were closely related and probably minted on Sardinia.
Here’s a specimen of MA series RRC 64/3. Schaefer thinks its is likely that all known specimens are struck by the same dies but not all are confirmed matches to one another because of quality of specimens.
Now let’s look at a specimen of RRC 65/3 (which is even more rare than 64/3)