解 (1)小明去分母时,方程右边的“-1”未乘6,得到的方程为$2(2x - 1) = 2x + m - 1,$将$x = -\frac{3}{2}$代入,得$2[2×(-\frac{3}{2}) - 1] = 2×(-\frac{3}{2}) + m - 1,$即$2(-3 - 1) = -3 + m - 1,$$-8 = m - 4,$解得$m = -4;$
(2)正确方程为$\frac{2x - 1}{3} = \frac{2x - 4}{6} - 1,$去分母,得$2(2x - 1) = 2x - 4 - 6,$去括号,得$4x - 2 = 2x - 10,$移项,得$4x - 2x = -10 + 2,$合并同类项,得$2x = -8,$系数化为1,得$x = -4$