Yes. It starts as a flat sheet, out of which is stamped the lug shape. It is then rolled and welded, and sometimes some rudimentary machining is done.

There's nothing wrong with stamped lugs; some custom builders prefer them because they are easier to rework than cast lugs. FWIW, cast lugs were introduced in bicycles as a labor saving invention, not because they had superior physical properties compared to stamped lugs. Cast lugs do have tighter and more consistent dimensions than stamped lugs which makes them more amenable to automation and requiring less clean-up, but a stamped lug in the hands of a competent builder is every bit as good.