I use to have a steering wheel off a late 70s early 80s Toyota truck in my 3rd Gen Celica. I'm guessing the spline for the steering wheel is the same for most if not all Toyotas.
I have an 1982 ItalVolanti steering wheel with an eBay quick release on an NRG short hub. My steering wheel had a six bolt hub like yours does. The NRG has 12 bolts and I'm guessing that's because it's made to be used with 2 different bolt patterns.
NRG part number SRK-120H
Hope this helps
Frankenstiened85 is correct about the NRG part SRK-120H. I just purchased the same short hub for my '77 SR5 and it fits. The only trouble I had were the 6 mounting holes didn't match the bolt holes on my Nardi leather steering wheel. I had to purchase a NRG quick release which had the 12 bolt hole and one set matched the pattern on my Nardi.