Marines

Early scenes depict the likelihood that no U.S. military adviser was used. No military Colonel would wear his rank brass sideways, and (this is an across-the-board condemnation of these costumers) no officer would wear overcoat brass, typically the largest piece made, on the collars or epaulets of his uniform. His brother officers would hasten to correct him in very short order. After all, "uniform" means just that.

Since the Russian officer wore shoulderboards which are standard issue, it was not possible for the costumer to make a glaring error there. Congratulations.