Some companies like to insert the plates in with the product with which they were used.
Other companies prefer to hold on to them and issue several products (and maybe even years) as its own product. (This is where our methods of cataloguing can make things confusing as we like to keep sets with the products they were released.) In cases like this, a release note or trivia item stating that the printing plates for this set were relased in another product would be very useful.
As for the plate you speak of, we have the plates for the base set listed and I found a listing on ebay for one - I see the sticker on the reverse shows a copyright date of 2016, indicating that these were, in fact, not released with the product, but I have not been able to find the info on the product in which it was released. Maybe one of our basketball experts can recall.
-- Dan --
Note: Please see my profile for more info regarding trading (section updated 3/4/2024). I have added a large portion of my inventory to the site, and currently have trading turned on (details are in my profile).