Issue is reproducible with Glassfish 4.0_b72 :
Steps to reproduce :
1) Install b72.
2) start the domain
3) Access http://localhost:8080
You can see the version as 3.1.2 instead of 4.0
Issued is resolved. Don't see the problem on build 80. Please update the bug to Fixed state.
FWIW, index.html is delivered as part of bundled documentation drop so this type of problem should be filed under docs subcategory. In any case, closing the issue.