Ignore the Amazon specs (most retailers in 99.9% of the cases just put what region they're located in than bother stating the correct region(s)), it's going to be the same disc worldwide. Paramount isn't in the habit of region locking.
Here are the specs according to Bluray-disc.de and the...
Grease 2 gets a separate BD release in Europe (Germany for example) so since I can't be bothered with the live version I'll pick that up down the line and won't bother with collection set.