The insignia on collars doesn't appear to be the block U. Or branch-specific insignia and their Model 1902 caps lack branch insignia also. Although it's difficult to see the hilts of the sabers (either models 1872 or 1906), they're worn hilt-forward, which regular army troopers of the 9th or 10th Cavalry wouldn't be likely to do.
The white trousers probably mean that the picture was taken either in summer or in the south, another indication that the young men are likely students at a HBCU. The item "ANTIQUE AFRICAN AMERICAN HISTORICALLY BLACK COLLEGE MODEL 1895 TUNIC SWORD PHOTO" is in sale since Saturday, August 26, 2017. This item is in the category "Collectibles\Photographic Images\Vintage & Antique (Pre-1940)\Other Antique Photographs". The seller is "theprimitivefold" and is located in Oak Lawn, Illinois. This item can be shipped worldwide.