Sorry I can’t see the picture. Found this online which I recognised from
Illustrated Encyclopedia of Uniforms of the American War of Independence 1775-1783 a book I have which unfortunately doesn’t give any specific details on the others ranks.
Of the three Spanish cavalry units which served in North America, the Dragoon’s of America wore yellow coats (no lapels) with blue waistcoat. See picture bottom row second from right.
Sorry I can’t be more help. Other contributors to this forum which much more knowledge than I will hopefully chime in