Lloyd, I shared a lot of my notes and info with Kurt for that article (old memories to dig up!)
1. I would not think so. The different belt sizes had different lengths and accessories, so were probably run in batches or on different lines. So the week on the tags are usually different from front belts compared to rear belts. That being said, the codes and tag info on a survivor should be within a couple weeks of each other and the stamped codes should also be very close, especially when comparing front males to front males, etc.
2. For deluxe, most of the examples I have seen were visible. Irwin standard D-rings were under the webbing.
3. The location depended on the year, the 68 version was under the hole, 69 versions were above the hole. If I recall the safety warning was changed between those versions too (maybe a federal thing?).