How to handle new Macs with Apple's Mac App Store apps?

If you look in the receipt file of a VPP delivered app you should see a truncated version of your organisation name in there, If you look in a vanilla version it won't be there, you could probably construct some kind of Extension Attribute around this I guess and then remove and replace.
Not sure how you would deal with versions that were on some other license (i.e. The user already has a license for the product).
There may be better ways of doing this as well.

/Applications/Pages.app/Contents/_MASReceipt/receipt

@Look Interesting. Thanks...I'll look into it.

@Look this is very usefull info for me , we try to deploy the "Free Apple Apps" via the VPP, but it has not been very effective. For one reason, we have a lot of apps just sit there and update when they like , week or 20 days after an upgrade has been made available via the AppStore, for others they don't even update after the original sync. its been very hard to track .

knowing that the 'Receipt" file is different in the directory mentioned above gives me an idea, although i don't know how to open that binary file and grep for the "VPP keywords" in it. if it does not have those, i could Delete those apps - that would re-download the Apps from the App store and they would refresh them selves. ...

Thanks for posting

@ChicagoGuy1984 Yeah it's mostly half encrypted nonsense. In our case though I opened them in TextEdit and noticed a partial string that matched our organisation, then using something like:

if [[ "$(cat THE_APP_RECEIPT | awk '/THE_PARTIAL_ORG_STRING/')" ]];

Should effectively return true if the string exists and false if it doesn't.