7 1/4 OEM spider gears help

Hello. I have a 64 Dart with a 225 slant 6 auto. I had a master bearing kit put into my non-sure-grip 9 bolt 7 1/4 diff. The mechanic said I should put in new spider and side gears. His parts pusher said he couldn't get the gears. I was tasked with finding some. I looked on line and found a bunch of sellers who had spider gear kits for 7 1/4 Mopars. They all had a long list of cars their kits were suitable for. The 64 Dart but also as an example 77-81 Town & Country, 78-88 Magnum, 75-88 Gran Fury, 87-96 Dakota, 77-85 LeBaron, etc. The gear sets options included Motive Gear, Richmond, USA Gear and others. I was suspicious when I saw the 70s rigs listed but purchased a set of Richmonds. They don't fit (as I might have guessed). My car is very original and I want to keep it so, and I don't want to change out the diff. I am looking for a new set of OEM gears. Do you have a set lying around you would sell me, maybe after you replaced your 7 1/4 with something beefier? Thank you Erick Johnson Western Montana (the car is currently in Calif waiting for gears)

Dart 2 4 20 2.JPG