I'm told that the "Engineers Certificate/Report" is only required for assuring emissions compliance for post 72 (or maybe its 73) vehicles....apparently, the RTA was letting that slip until a couple of years ago, then they started to require it.
I haven't been paying that much attention as my 71 wasn't affected.....but from what I've been told, yes there is a requirement for a 77 T/A to have a report done......bloody rip off when the car already comes with a non-vented cap and a carbon canister....which is about the limit of what needs to be complied with.