Just read both. I don't see any continuity differences in them. They only added that he decided to recreate the serums and keep them locked away until "the world may be ready for them"
That's right. Read also my posting here: viewtopic.php?p=2838#p2838
It's definitely not out of continuity, but - as far as I know, could be wrong here - it predates the 'Marvel Comics'-brand. So when you put the first appearance of Ant-Man in The Order, you've got to include the complete Sub-Mariner, Captain America and many more. I think that's the problem.
I'd just change the issue note:
Henry Pym previously appeared in Tales to Astonish #27, however this is the first real appearance and tells some of the #27 story differently.
...in something like 'read Tales to Astonish #27 first, although it predates Marvel Comics' or something like that and all is good.