Southwest Native American antique pot

My grandmother received this bowl as a gift in the 1940's. (She passed away last year at the age of 95.) She said she was visiting on a reservation somewhere in New Mexico I believe. She and my grandfather lived in various parts of New Mexico and the southwest when my grandfather worked for the railroad before and during WWII. She and some of the other railroad wives would visit the reservation and take donated clothes and blankets from time to time. An elderly lady took it off a fire and scooped out beans and gave the bowl/pot to my grandmother. There is a smoke/burn mark on it. There are also intials I think that read F.T.S. or F.T.C. It's pretty heavy. No cracks or damage but there are scrape marks inside and the outside is fairly pitted. I've never cleaned it; I like the markings on it. (Obviously it washed out after the beans!) I'd love to know more about it. The closest thing I can find on the pattern is San Juan Pueblo.