Nice save of a neglected plant. Now that you have it happy it will probably do well in coming years. It should be a vigorous hybrid.
There is no hybrid in the Cattleya alliance called Green Emerald except for C. Green Emerald. This appears to be that hybrid, really no doubt in my mind that it is. It has no ancestry that was ever Brassavola, Laelia or Sophronitis, so I think Pot was a mistake that crept onto its label at some point.
'Queen' may also be a mistake. 'Emerald Queen', 'Orchid Queen' and 'Queve' are awarded cultivars that logically may have been widely distributed. They are all very similar in appearance and virtually indistinguishable from this picture. Any could more easily morph into 'Queen' than Cattleya being replaced b Potinara. There's no way to know though, and no harm in calling it 'Queen' if it isn't judged for an award.