I hope I can clarify this a little:
The GAC was created by
Gucci Perfumes division in 1979 (until about 1990). Gucci already had coated canvas luggage and a small accessories line but the GAC was like diffusion line and sold in dept stores, airports etc. Because it proved so popular and profitable it the line was extended and extended again, sometimes in annoyance of 'old school' customers. The 'proper' coated canvas luggage, travel accessories and other smaller accessories continued to be sold, they were just not part of GAC. In the very early 1990s GAC was phased out, but to inject cash into the company canvas bags in a similar vein were sold in Asia, most specifically Japan.
The Gucci shield is much older, from 1955. Many bags had the shield as a 'pullee' (or charm) for the 'new' feature of an inside zip, and can be seen on bags right through the 1960s. NOT all bags from this period had a Gucci Crest charm, usually the 'proper' handbags. The shield charm feature was reintroduced in the 1980s. There is also an abstract shield shape that was used on some bags in the early-mid 1970s, but this was on the outside of the bag. The Babushka collection in A/W 2008 featured the shield again.
Gucci's trademark logo changed frequently and not just depending on the date. The size and what was written depended also on what fitted the bag itself as everything had to be in-proportion. Confusingly, not all items of the same date have exactly the same markings. Some bags have to be dated from adding many features together rather from a single logo, many re-issues of the same bag complicates matters further but there are usually clues as to the bag's or item's age. There are also custom pieces that fall outside the normal parameters of expectations, usually they have a different script logo but occasionally not.
From the 1950s onward, as Gucci reached international clientele, 'Made in Italy' or just 'Italy' under the Gucci logo, paid in homage to the high reputation Italian leather goods had/have around the World. The conventional wisdom was to think of the best fashion from Paris and accessories from Italy, which is why even when a French (fashion) house had a leather goods line they were mostly made in Italy including YSL, Dior, Ungaro and Chanel (also some made in France).
The GG-print was developed in the mid-1960s, from the earlier original diamond pattern and the new GG logo in the mid-1960s, the GG pattern was featured and expanded in the the very early 1970s even onto rtw as a gimmick. The Diamond pattern re-occurs throughout Gucci's history as the GG-print does also. The mono print gets copied most often by fakers because it's the most obvious outward display, just like LV's mono print. If you look at a typical GG-print there are little spots that make up the old diamond pattern, these little dots are also turned into the 'popcorn' chain link and design features for lots of Gucci's jewellery along with the diamond pattern and the horse-bit etc.
The plaque is from the 1980s, the shape of tag varies, depending on the date.