Andrew Gideon wrote:
Some work was done on an airplane. The new W&B is of the "removed/added"
sort and computes a new empty weight and moment arm. But the document
doesn't state the gross weight.

Mine doesn't. The gross weight and the CG envelope are listed in the
operating limitations book. The Type Certificate requires the
equipment list AND the operating limitations book.

There's no specific requirement for W&B paperwork in the regs despite
what your flight instructor told you.