  We construct local M-operators for an integrable discrete time version of the
classical Heisenberg magnet by convolution of the twisted quantum trigonometric
4$\times$4 R-matrix with certain vectors in its "quantum" space. Components of
the vectors are identified with $\tau$-functions of the model. Hirota's
bilinear formalism is extensively used. The construction generalizes the known
representation of M-operators in continuous time models in terms of Lax
operators and classical $r$-matrix.
