Well with the amount of 1ks in the stack also, it wouldnt be more than 300 T5ks. One rack of 5ks is 500,000. With 1.9mil on the board, it would seem like it is prob 3 racks of T5ks and some racks of T1ks. It wouldnt surprise me if the T5ks are out in the wild already to be honest. Considering this was 1990, that is almost 30 years ago. No telling where they ended up.
There should be lots of T500s though out there. No telling where those are.