Apparently the service menu coding is incorrect and out of date, its not the best way to check for WBC older panels or the newer WBE or OLED.EX panels.
Check this post
here
From my understanding of that post(
could be wrong), if you check under General>OLED Care>OLED Panel Care>Pixel Cleaning> then read the bit on top with pixel cleaning.
If it reads 60 minutes you have the older panel I believe, if it says 10 minutes then its the newer panel. Not that there is any real major difference still.
Its quite possible many 42C2s were already on the newer OLED.EX panel after all, hopefully am correct on the above but feel free to read his
guide.
Further edit, WBC and WBE are the older panels that use 1 hour pixel refresh. OLED.EX is the latest panel that uses 10 minute pixel refreshes. info
here