This is just a large date normal design for that year. The devices are different on the small and large date coin master hubs. The large date design is the same, but the old master hub has swollen and this the devices are also enlarged and relocated. This happens to the hubs as they age from creating many master dies though the years. How I know that this is the issue? I took a small date design and altered it in the same direction as the die wear happens:

This is the normal small date for that year. Note the location of the devices and the sizes of the devices.

This is the altered image, and it looks exactly like what happens when the master hub swells from the creations of the master dies. Here is a side by side of that they would look like:

Here are the coins side by side:
uploaded/coop/C1982_SMALL_DATE_LARGE_SBS_ZINC_AAA.jpg

Movement of the devices:


So it is the same design, but with the swelling of the master hub, it alters these large date coins. Realizing the issue on these old master hub, they recreated a new master hub, and thus we have the small dates that year as well.
CoopHome:
Why do some years has large and small date designs? recreated master hub.