Very early Bach, all off his double concertos use a fugal texture, and it's perfectly imitated here. It really does sound more like a concerto for two soloist with string orchestra accompaniment, a quartet could play it, but I think it would sound a bit anemic, at least three instruments to a part or maybe 3,3,3,2 would be a better balance. It's nicely written, I would have loved to hear more from the second movement though.
Vernon