Sorry to hear about Parak's rubberdomes. That does suck...
These NCR boards are actually quite interesting. All HO150-STD1-12-17 keyboards have NCR or AT&T branding. Some have a white case, while others are dark grey, much like an industrial Model M. As far as I can tell all dark grey versions are NCR branded, while the white ones can either be NCR or AT&T. All of these boards were made by Cherry, but not all were G81's. Mine is a G81-3077 SAU, but many others are actually G83-3077 SQU boards. And yes, I've wasted some money on a few of those already. Unfortunately that is also likely why Parak ended up with rubberdomes - correct NCR model number, but wrong Cherry number. Only a small percentage of these HO150's seem to be G81's. I'm sure there are a few more out there to be found though.