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)
Liv Mariah Yarrow 
Yes, there are some features that suggest the same die, Liv, but one big feature says no. Look at the hair on the top half of Saturn’s head. On Arte. Asta sensa riserv.(RRC64), the curved hair is ~horizontal. On NY2(RRC65), the curved hair is ~vertical. Do you agree?
The only other example to help is NAC 61 in RRC65. The top hair looks ~vertical there also, but NY2 is clearer. BTW, I would agree the engraver is probably the same, or at least a master and pupil.
Sorry,
Richard
I must get my eye back into it. BUT if you have doubts, I have doubts. You’re eye is superior to mine.