Just came across this discussion and thought I'd offer the possibility that the sword is not a M1850 Foot Officers Sword, but MAY be a M1850 Staff and Field. The photo and position of the sword make it hard to determine exactly, but seems to me that the guard is wider and fuller than a Foot sword. The branch on the guard closer to the grip looks to have more embilishment between it and the grip than on a Foot. Just an observation, but would clearly elevate the soldiers rank considerably. Length of both swords is almost identical, so no impact on his projected height.