The 04D equals the 4th week of April, 1970 as the build date.
The "A" indicates black as the interior trim color and zero exterior trim options
I believe the other numbers are Fisher Body numbers that relate to certain options on the car...there is very little information available about what these numbers mean. They have been discussed before...some folks may have more details...
There are many trim tag codes that have never been deciphered. It's also complicated by the fact that different plants had different codes. The trim tags contained body build info for Fisher Body workers. That we can decode even some of what's on them is a bonus.