Ultrix plates were much later.  The original Unix plates were there for a few years. 

On Tue, May 10, 2022 at 8:58 PM Kenneth Goodwin <kennethgoodwin56@gmail.com> wrote:
As I recall, The UNIX plates were the first in the series and distributed at a USENIX conference AT THE DEC booth The next year, they came out with the ULTRIX plates.

On Tue, May 10, 2022, 8:54 PM Steve Bourne <srb@acm.org> wrote:
Armando also responsible for the UNIX "live free or die" plates. I still have a few.

Steve 
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