Certainly if you have a VBM for 1980, for example, the Law/Reg book has 1980 data for an alleged 1980 CUE - I mean - if you are going to allege CUE for a particular year you need to know what the law/regs/DC's were for that year, so a 1996 VBA is useless, although it might refer to an earlier reg or law in some footnote, but it's doubtful that would help a specific issue. I have located a service called HeinOnline that (for a fee) allows one to access old law and regs, State and Federal and appears to be the answer to going back to the fifties if need be.