I have a 2002 suburban 1500 4x4 LS trim line

It came from factory with exterior two tone paint. I have the GM build sheet and the RPO sticker / codes (see attached).
The exterior color code on RPO sticker is 50U for exterior and 92D for interior.

However, there is no color code on the rpo sticker for the secondary exterior color. The Build sheet states exterior color as "50U - Summit White / Med Charcoal Gray" - which is only reference to exterior color on the build sheet. Build sheet does call

I have googled looking for the color code for the exterior secondary color but can't find anything in GM's, BASF. PPG, AutoColorLibrary.com etc catalogs/websites that list a "Med. Charcoal Gray".

Does anyone have idea(s) how to determine the secondary color (exterior)?

Thanks!