I think I may have found a significant indicator that the spoons were indeed ordered and marked for Frank Jay Haynes to sell.
In a document called Yellowstone's First General Store A Legacy of Jennie Henderson and Her Family by Robert V. Goss states
" Jennie decided not to continue as Postmaster. She submitted her resignation to the Post Office Department in a letter dated January 10, 1906, and recommended Alexander Lyall as Postmaster on February 6, and he began sharing in the operation of the general sore. By that time, the store was dealing in "Game Heads, Fur Rugs, Souvenirs, Agate Ware and Indian Curios, Indian Baskets and Navajo Blankets and Specialty, and Kodak Supplies," in addition to curios and general merchandise. That year, Jennie discovered that photographer Frank J. Haynes was selling souvenir spoons and leather curios in his photo shops - items that she felt were not within Haynes's merchandising rights. Together with Henry Klamer from the Old Faithful general store, she filed claims with the DOI (Department of Interior) protesting Haynes's actions. Haynes defended himself by asserting that he could indeed sell those types of items, as long as the were embellished with his park views. This time the DOI sided with Haynes, and he was allowed to continue retailing those types of curios."
On these spoons there is a depiction of the giant geyser one of Haynes more prominent and recognized Yellowstone National Park photos/views. I can imagine that because of this indecent with Mrs. Henderson and the DOI that he began to mark his spoons with his last name as well.
And as for R. Wallace & Sons Mfg Co it was not unheard of for them to take requests with specific detailing/design for souvenir State/Union spoons.