There are a lot of "Nationals" from Guanajuato in Texas, and by appearance, many from Zacatecas, but this is only my coincidental observation.
Yes; isn't it strange? When I was young, if you saw a very fair, light-haired, light-eyed Spanish-speaking man doing construction or farm work, you could almost guarantee he was born in Northern Mexico. Today's (mostly illegal) immigrant workers come from the South of Mexico and don't look like that.