Did Michelangelo really have a stonemason's mark?

Ludwig Goldscheider, Michelangelo (Phaidon, 1973) has this insignia on its black cloth hard cover: three rings triangularly set and initial M in one of the rings. and and "Michelangelo" callgraphied underneath. His sheets of drawings used to guide quarrymen in cutting stones for his projects, particularly c. 1520 all show this three-ring design and a work, unfinished, in the Accademia in Florence called (erroneously) the "Atlas Slave" still shows this three ring design on its upper-most face, a surface never touched by the act of sculpture. Michelangelo apparently created his stone mason's symbol using an early, and similar, symbol used by the Medici Family. He said the circles represent "Sculpture", "Painting," and "Architecture," contemplation of which "raises the thoughts to heaven."