I have what looks like a unit pin/crest that my grandfather brought back with him from WWII. He was in the 3429th ORD MAM, but I also know that he was transferred to the 423rd Inf in the 106th in spring of '45. He also brought back a 75th Inf. DIV patch which could have placed him there as well.
The pin is silver and blue, with the phrase 'AD ALTA' at the bottom of the crest. The crest has three swords that all point in: