SHOF , I really do not think this would be a legal issue per se but a “fraud “ issue . Although my experience with re stamping engines is with older SBC’s . When would do a serious deck job it often eliminate the numbers and would ALWAYS put the old number back on .it would NEVER leave the shop blank . We had a situation where we decked a 265 and left it blank next thing we heard guyre-stamped it with corvette F &G codes and asking big bucks .
Ps. We put the word out on him