I'm really old then!
I remember using 3 digit phone numbers in the Pittsburgh area. Then they added a prefix to make it 4 digit and then 1 digit for 5 and then 2 more using letters. So, phone numbers once had 2 letters and 5 numbers, such as ULysses 8-9941.
Anyhow, back on topic, the old gelatin plant was about 20 miles west of Rochester NY in LeRoy. If you go to Google Earth and slide South West to LeRoy on 490, you find the Jell-O museum which is now a paintball arena as well. I've played many games there with friends and grandkids.
Over time, Knox has added and removed many extraneous ingredients to their plain unflavored gelatin. I have seen Dextrin, Sodium Silicates and other items in it to prevent spoilage, add a touch of flavor and prevent caking. It is also not as highly refined as regular Photo Grade gelatin. In addition, IIRC, the Bloom Index is rather low giving it more swell and less hardness per unit weight. OTOH, people have used it to make emulsions.