My dad moved to FLA and unfortunately some of his collectibles did not go with him. He started collecting these over 30 years ago.
My dad served in the Army reserve in the 60's and why he collected these. These ingots were packaged in cachets - envelopes with stamps that were postmarked on the 200th anniversary of the event shown on the ingot. This is one of a number of combined medal-stamp sets known as Medallic Commemorative Covers, but this set has the largest silver ingots. It is seen fairly often, although not always as a complete set.