And I stand corrected on the Great Seal...as you say, the first depiction was in September, 1782, although it was described earlier that year.
I was mistaken since I thought the first depiction was over the Washington family pew in St. Paul's Chapel (Episcopal) in NYC (April, 1789). This is where The General worshiped for the first 15 months as POTUS.
Thanks for the follow-up, SC.
I wonder if that photo I linked above had the Great Seal added later (but still in the 18th century)?