To help narrow dates down, Haverly was appointed as a PM March 1, 1865 according to this order when he was sent with his company to Fayetteville TN. Could this execution have occurred there? The 42nd as a regiment was still headquartered at Tullahoma but was scattered about the country side with various picket and guard duties see: https://sparedshared23.com/category/42nd-missouri-infantry/

The March 1 order is here:
https://www.fold3.com/image/233991762

His muster card identifies him as a Blacksmith from Macon MO. He apparently was appointed Special PM in Jan 1865 per this card:
https://www.fold3.com/image/239510231

He had served 3 years as a blacksmith and Pvt in Co H 22nd Regt MO Infantry enlisting for 3 years on Aug 1, 1861 in Macon City MO.
https://www.fold3.com/image/231632281

He may have spent some time in the 10th as well, working on tracking that down
1890 Vet census:
https://www.ancestry.com/sharing/10038664?mark=7b22746f6b656e223a22544d41754e74395758424b43304453687a49694479675633537a4447314e6e335568316475784c4d3732493d222c22746f6b656e5f76657273696f6e223a225632227d