Is crest syndrome with high centromere b antibody considered a rare disorder with rheumatologists having only a few such patients? should i seek out a scleroderma specialty center for regular care?

It's your call: I'm glad that you got your diagnosis. It's your call whether to seek a sub-subspecialist. Often your best move is to become scientifically literate and read the real journal articles having to do with your disease. The key decision in your management will probably be whether, when and how to manage any pulmonary arterial hypertension. See if you have someone locally who you like & trust.

No: Any rheumatologist is well-versed in this disorder, and you should have one there in amarillo or in lubbock.

Yes: Most rheumatologist will have only a few patients with crest syndrome, if any. If travel is difficult, a specialty center may be able to work with your local rheumatologist to provide the best possible care with a minimum of travel.