If your talking about the top of the dash above the instrument cluster then yes I have heard that they do crack. I don't even have a dash it has been broken off. I found one at the local wreckers and he wanted $45 and I wasn't sure if that was good or not.
mines still the same 1987 built still looks new mat was never on it or shades used.. just use abit of amorall spray whenever you think its gonna dry out