I don't think Dakota made any in this configuration, at least I've not yet seen one. The 280AI wasn't a SAAMI cartridge until the very end of the Dakota era. Anything is possible, but I think the odds of finding any Dakota in this caliber are pretty low, far lower with the requirement of a 76 vs a plastic 97.
Based on the era if you did find the one in a million gun, I'm sure you're aware it will be for the original wildcat loading which is not compatible with factory produced SAAMI ammo which is slightly different.
Just trying to be helpful, you might want to find the nicest, least expensive Dakota 76 that pleases you (e.g. a lower value proprietary Dakota caliber) and send it to Parkwest for a rebarrel to your preferred version of 280AI.
Good luck in your search, please let the forum know if you find one or learn how many were made.