How to identify assembled top case after MBP repair?
The iconography on the 2018 keyboard does differ from that on the 2017 and 2016 keyboards. This can be used to identify the generation.

The YouTube video New 2018 MacBook Pro Keyboards MIGHT fix Keyboard Problems shows the differences between these three models' keyboards. The 2018 option key has a far taller icon than the 2017 option key.



The MacBook Pro 2016 and 2017 models will not receive the 3rd generation MacBook Pro 2018 keyboard according to the MacRumors article: Apple Says Third-Generation Keyboards Exclusive to 2018 MacBook Pro.