This issue has variants.
The on-sale date is the publication date reported in the U. S. Copyright Office filing.
An earlier indexer provided an on-sale date of April 12. No citation was given, although other indexers speculate that it may come from a listing in the fanzine The Comics Reader.
Possible Verpoorten inks per Nick Caputo, August 2012. Marvel Comics Index #8A lists Frank Giacoia as inker and Gaspar Saladino as letterer.