Let $f$ and $g$ be twice differentiable functions on $\mathbb{R}$ such that $f''(x) = g''(x) + 6x$, $f'(1) = 4g'(1) - 3 = 9$, $f(2) = 3g(2) = 12$. Then which of the following is NOT true?
(1) $g(-2) - f(-2) = 20$
(2) If $-1 < x < 2$, then $|f(x) - g(x)| < 8$
(3) $|f'(x) - g'(x)| < 6 \Rightarrow -1 < x < 1$
(4) There exists $x_0 \in \left(1, \frac{3}{2}\right)$ such that $f(x_0) = g(x_0)$