She looks like a Swiss/Nubian cross to me-maybe a Nubian/Saanen?
That tag looks like it is either a electronic tracking tag, or a identification tag. And unless she came with papers, no, she is not registered.
The owner would know. One of the first things to do when you want a goat is- do your homework. Then once you buy, ask to see everything. Registration papers (if any), vaccine records, worming records, date of birth, breed, mother, father, etc. Sorry if I got carried away.:doh:The tag is probably either identification or tracking, and she looks maybe Alpine/Saanen, Togg/Saanen, or something else crossed with Saanen.