I will go 64 BN or blue as well. However a questionable color wouldn't surprise me here. My avatar coin was in a PCGS questionable color slab when I bought it. It now resides in an NGC MS64 slab.
The obvious answer here is MS65BN. But every great once in awhile you see one of these tagged RB. So I'll go MS65RB.
Looking at in in this forum, I agree MS64BN. Close to 65. It is slabbed, what is the grade on the slab and by which TPG?