Many, if not most, were from the sizable Lebanese community in Mexico who found that trading in Navajo Jewelry and Art (real and imitation) was very profitable. Low overhead, high margins and high turnover plus an endless supply of gullible customers (who couldn't tell a Navajo from a Lebanese) delivered to their doorstep via I-40 made for a perfect setup for culturally sharp traders.
That, plus a mostly cash business under the IRS radar, made a bunch of Lebanese very wealthy.
But you had to live in Gallup.