If you're jonesing for a single copy, you could go the repro route. Neo Old Store's repros are good quality. Every bit as good as NCI without all the conflated "limited edition" bullshit and bloated ebay prices on pirate goods. Their site says "conversions" but there are no authentic games sacrificed here.
Still, probably best to get a NeoSD solution for these types of games where you want it specifically on AES and there was never an official release.
www.neooldstore.com
Also, since neo-geo.com directs to the forms now, the Master List is quite handy to tell what got an official release on which SNK platform:
https://www.neo-geo.com/snk/masterlist.htm