[Boquillas]

I believe there are a few primer layers over the tyvek, then stucco is applied, then it is painted. The white stuff doesn't look like stucco from what I can tell--it might be an underlayer. The stucco looks like it's been tinted dark brown so as not to interfere with the final paint layer of light brown. I could be completely wrong, as I haven't been down to look at the site.