The only way I can figure this, is to find out when certain UPC's were issued. There ahs to be some sort of UPC database of that sort out there.
Someone mentioned maybe finding old TTI paperwork in a storage shed somewhere. I doubt that. I recall in the 90s, when they moved to another warehouse. I asked them how it went, blah blah blah, then asked if they still had anymore of the turbo force magazine sitting around, since in my last order they had thrown in a few, and I recall them telling me they had a lot of them left. The guy on the phone told me they threw them out during the move. I was younger, and let out a surprised, "WHAT?!? I would have taken them!". I was then told, if I had let them know, and paid for shipping them, I could have had them, but they weren't going to ship box(es?) of Turbo Force magazine to me for free. I mentioned they could have thrown a free one in each person's order instead of throwing them all out. The person on the phone let me know that's a lot of trouble, to throw them in as a freebie for each order. It was easier to trash them all before the move.
So, lots of stuff was thrown out.