Sure but there were a bunch of technicians there with Howard, and he by no means would have been able to do it on his own- as a matter of fact, we know for a fact that he spent the remainder of his life unable to replicate Erskine's work (along with everyone else in the world, including Bruce Banner's failed attempt) because Cap is still the only super soldier when the Avengers happened. So he ran the technology, but we don't know for sure whether he developed it himself, or built it according to Erskine's plans/specifications, or what- I don't get the feeling that he and Erskine had had much contact prior to Cap's transformation, judging by their interactions that day.

And clearly. He wasn't a superhero/Avenger then, he was just a little guy with a heroic soul- and like I said with the grenade incident, he still would have been capable of brave acts that saved lives. Just not nearly as much as post-transformation when his outsides matched his insides, to use a cliche.