Are you sure that the WW1 and WW2 grays were not the same?

According to Gröner, these were the same colours. This paint scheme was introduced in 1896 and used colours that were later called RAL 7000 and RAL 7001, but were previously known as hellgrau (50) and dunkelgrau (51). Despite their names, these were both light greys.

It is true that the paints were only standardised to RAL later. But also the Reichsmarine and Kriegsmarine did not use RAL numbers until 1944.