It's also, not a very large piece. Maybe 50" high.
That helps it, could be a lady's desk, the smaller the better for sales. Mart would know value of this era better than i would but, desks in general are going for a song at auction as they don't fit modern requirements for desks (think puters) you can get a period 18th century slant front desk in good condition for 1k or less these days. Yours still has the gallery on top and that helps it to as they were often lost over the years.