There is no complete "official" Foreven Sector. Beyond the basic information provided GDW (back then) the publisher will not go in there and rewrite info relating to the sector, thus invalidating all your hard work. OTOH, your work will never be "official", no matter how good your work is.
This was pretty much the same for First Survey.
In the modern context, as John says, Mongoose offered it in the Mongoose SRD, If you want to OGL some stuff and have it take place in the OTU 3rd Imperium, get a licence and have it take place in Foreven Sector.
Again a basic info doc with hex locations, a few worlds were provided. But if anyone could get a license, your Foreven Sector would be no more official than anyone elses...
If you want to be nit-picky, it is only these sectors and these times as in other eras the sectors are possibly filled in like Zarushagar is in 1105 and 1248
Milieu 0: Delphi, Fornast, Zarushagar (T4, First Survey, Imperium Games)
1105 Golden Era: Foreven (MgT1e, Mongoose SRD, Mongoose Publishing)
1120 Rebellion: Foreven (MegaTraveller, Imperiallines #1, GDW)