Three months after that first issue hit the stands, THIS appeared…

…which Stan described, in the issue, as a "test" to see if modern readers wanted Cap back.

Now, assuming things were being done on a normally realistic schedule for that time, Stan and Jack would have produced that STRANGE TALES story, in order to hit an August on sale, sometime between March and May of 1963, The fourth issue of THE AVENGERS, done on about the same schedule, would have been produced sometime around July/August of 1963.

This doesn't tell us very much -- except that Stan and Jack would likely have been working on AVENGERS 4 very close to the time STRANGE TALES 114 was hitting the stands. Given Cap's prominence in following AVENGERS issues, the response to his "return" in ST was either phenomenal, or the "test" was just standard Stan hype, and they were planning to bring him back all along.

If they were working a bit tighter on their deadlines, say four months ahead of publication instead of six, then there is room for response to ST 114 to have actually caused the story in AVENGERS 4.

Too much detective work, for me! And Stan, of course, would not likely remember!