The on-sale date is the publication date reported in U. S. Copyright Office filings.
The on-sale date matches the front-cover stamp on a copy owned by an earlier indexer (Bruno Andreacchi).
Conflicting credits; Steve Ditko per (Bob Bailey, 2005-03-19 & Nick Caputo 2006-08-31); Jack Kirby (Nick Caputo, 2005-01-05) (Per Sandell ed.) // Inker comment by Bob Bailey: While he was not well known for doing war comics Ditko did do a few. If you compare the inking on the cover to Sgt Fury #14 which was inked by Ditko over Ayers (or any of his other Kirby-Ditko collaborations i.e FF 14 cover, FF 13 interior) you get the same effect in the muscles, clothing, sand, water and Dum-Dum's hand. Also Nick Fury's rounded shoulder and facial wrinkles are definite Ditko.
Per Caputo: I've read Bob Bailey's comments about Ditko being the inker for this cover,and I have to admit that I suspected him as well, although I'm not entirely convinced. There were times that Ditko basically went over Kirby's lines instead of embellishing them, as he usually did (A Giant-Man story and Strange Tales Annual 2 are two instances), so its possible the sparse line I see in Kirby's inking may be Ditko following the lines.
Chris Boyko: Steve Ditko (in litt., 18 Oct. 2014) states he did not do the inks on this cover and also does not think it to be the work of Dick Ayers.
Original indexer credited Dick Ayers.
credits per Nick Caputo, March 2013.