org-latex-tables-booktabs

org-latex-tables-booktabs is a variable defined in `ox-latex.el'.
Its value is

nil

Documentation:
When non-nil, display tables in a formal "booktabs" style.
This option assumes that the "booktabs" package is properly
loaded in the header of the document. This value can be ignored
locally with ":booktabs t" and ":booktabs nil" LaTeX
attributes.

You can customize this variable.

This variable was introduced, or its default value was changed, in version 24.4 of Emacs.