It's been a real surprise for all Italian guitarists.
Few months ago someone posted this on YouTube:
https://www.youtube.com/watch?v=UmTQYquqxSYit's from an old (1965) Italian TV program, called "Chitarra amore mio".
The guitar player is an absolutely unknown amateur self-taught guitarist called Vittorio Camardese, Radiologist in a Rome hospital. Nobody knows anything about him (he died several years ago), but it seems evident that E. Van Halen and Steve Hackett were not the first ones to use this technique.
Consider also that in 1965 classic guitars were not amplified: so, to have a decent sound, tapping had necessarily to be not only precise, but also very, very STRONG.
The only news about Dr. Camardese are actually just what he says in the brief interview, before beginning to play: "I'm just a doctor, I had to ask permission to my Director at the hospital to come here to play (!!!), I don't know if someone else plays this way, it's just my way to play guitar, I've always played this way. I've never studied music, I cannot read music".
And when the interviewer asks him about the possibility to have a score of his music, he says "There's no score at all, I play what I like by ear. I couldn't write any score".
Alfredo