There is a stamp on the back of the shell, under the C-stick. There are a few variations for this stamp, and it’s a great tool to identify what kind of internals it has.
Blank: This is found on the controllers made with T1 internals. It can be found on the Indigo, Jet Black, Spice Orange, Indigo/Clear (rarely), and on the Panasonic Q SH-TGC10 as seen here.
DOL-003 is the model number for the GameCube controller.
This stamp was used from the launch of the GameCube up to around the launch of the GameCube in Europe on May 3rd 2002.
CE: This is mostly found on controllers with T2 internals, but can also be T1 for the Indigo, Jet Black, Spice Orange and Indigo/Clear. Even though the Indigo/Clear is almost solely T1 in the US and Japan, it almost always has the CE stamp.
CE stands for “Conformité Européenne” (European Conformity), and is a certification mark that indicates that the product follow European conformity guidelines.
This stamp was used from around May 3rd 2002 up to 2003, where Nintendo stopped production for the first 9 months of 2003.
CE•: This is found on almost all the variants, except for the Panasonic Q SH-TGC10. It is solely T3 internals. The Indigo/Clear was made as a T3, but only in Europe.
This stamp was used from around September 24th 2003 up to the demise of the White GameCube controller sometime in 2014.
•: This is found on Indigo and Jet Black controllers. T3 only.
Since there is no CE marking, I assume it wasn’t certified for the European market yet, so most likely early production after the 9 month production hiatus in 2003.
CE• Made in Japan: Found exclusively on the Indigo and Jet Black controllers, T3 only.
I assume the production of the GameCube and its accessories was briefly brought back to Japan after the 9 month hiatus in 2003. As far as I know those are solely found in Japan.
• Made in Japan: Found exclusively on the Indigo and Jet Black controllers, T3 only.
Same as above, but since there is no CE marking, I assume it wasn’t certified for the European market yet, so most likely early production after the 9 month production hiatus in 2003.
Trash Can: From the Smash 4 controllers onward.
It was also present on a few White controllers from 2008, which means it was probably intended to be sold on the international market, either early or late into its production.
The trash can and black line symbol, called the “Waste Electrical and Electronic Equipment Directive” (WEEED) is a set of directives from Europe that sets recycling targets for electronics. It is required on electronics distributed in Europe, and the black line means that the product was put on the market after 2005.
The triangle with a check mark (Regulatory Compliance Mark), simply means that the product is safe to use and is required on electronics in Australia.
The VCCI mark (Voluntary Control Council for Interference by Information Technology Equipment) is a Japanese set of regulations on electromagnetic interference, and is required on electronics in Japan.
DOL-002 (BRA): A simple sticker put over the original stamp that says “DOL-002 (BRA)” instead of DOL-003.
Nintendo had a partnership with Gradiente to produce GameCube parts for the Brazilian market. Not much is known, I’ll update once I get my hands on one.
Thanks to Mateus Lacerda for the picture!