Also, I think the 1076s didn't have the magazine safety (or maybe the guns made for FBI didn't have it).
The 1006 is a bit more rugged than the 1076
1006 = 5" TDA slide mounted safety/decocker
1066 = 4.25" TDA slide mounted safety/decocker
1026 = 5" TDA frame mounted decocker
1076 = 4.25" TDA frame mounted decocker
1086 = 4.25" DAO/slick slide
Don't forget the 1046!