much, or most all that appears sculpted is hammer- punched from the back of the piece. the front is usually placed in a pitch bowl or some such material to lend support to the blank. all the dimensional aspects are done from the back. this is done with a small hammer and a variety of shaped punches of different sizes to suit the design. engraving follows to finish the job.
Nice work. If it was done from the back, face down in the pitchbowl, it's called repousse as I understand it. Chasing is done from the top. There are other differences as well but both techniques are often used together. Sam's instructional, where he sculpts without removing metal, would be classed as chasing.