All wineries are good.
We are members of Harvest Host and will not pass up a winery, brewery or distillery if convenient on the way for boondocking. I haven't been to the Galveston Winery.
They may get their grapes in the form of juice concentrate for making wine from California anyway if they don't have vines locally. If they have vines you will probably see them surrounding the winery. I recently stayed at a Harvest Host winery in Willcox, NM not too far from Texas and their wines were excellent. So they had their vines close to Texas but not all their offerings were made from their grapes.
We have three craft wineries within 6 miles of our house in Victoria, Minnesota. Use to be growing grapes was next to impossible in Minnesota because of the cold winters but the University of Minnesota Horticultural Center developed winter vines that could stand the cold. The center is 1/4 mile from our house. Marquette is their top produced grape and is now grown by most wineries in Minnesota and Wisconsin.
Go for it. If they are offering tours and tastings they probably won't be bad. That's my experience. You won't be having 3 buck chuck wine there. A glass will probably cost 3 times that much.