Wow! No, I didn't have this information on my coin so I very much appreciate your posting it. The coin looks much better in hand and in its color picture than in the catalog picture. Also curious how Triton XI described it as "EF - Lustrous" while the old catalog lists it as "... almost very fine." It's certainly much more the former than the latter.
I definitely agree. This sale was very, very conservative with grading. Even some of the magnificent boscoreale pieces which are now universally graded as Good EF/FDC were graded only "almost EF".
I managed to track down the original article from 1938 which has your coin photographed. Definitely a valuable additional part of the provenance!
As I recall, the Met did not really care about the pieces. I believe they were on loan to the ANS and not being displayed. I also recall reading or hearing somewhere there may have been pressure to sell from some donors, I cannot remember where I saw that. I think the Museum as a whole was also in financial trouble. It was a very large sale, it brought in something like 2.2 million for just the roman gold.