[July 30 / Server Check] MapleStory

That's extremely hard to know, you'd have to go through and check every single item in the cash shop versus every item in the data. Even if someone started doing this, I doubt they could finish before we already knew whether the patch would be this week. XD

An attentive person would be able to identify items which are DEFINITELY out, and make up a list of items which could possibly be unreleased. From there, they'd just need to write down their list and punch it into cash shop and cross reference to see which items they thought might not be out that actually were.

It would take a lot of time and effort, but it certainly wouldn't be impossible to complete over the weekend, not if the person puts in many hours.