How to find colour of paint block

[Wibs]

Hi,

The client made a paint block with different colours - some of the fixtures are yellow, some are pink.
How do I find out the RGB(WW) values they used for this so I can use the same values in a different effect/block?

The long and hard way would be to get a DMX level analyzer, connect it to the output of the controller and see what is shows - but that seems a bit too much :)