No.

Nothing to add to @AlexP answer, except that, for a comparison, the Manhattan Project's main difficulties were in getting pure enough materials and precise enough tolerances. In other words, even knowing exactly what something is and how it works (and here we have neither, not "exactly" enough), you still have the problem of engineering it.

So, no way a failed assassination might help Nazi Germany.

...and it gets worse.

By the same token, even a failed assassination might spell utter disaster for Nazi Germany, because of its implications.

"So, Herr Doktor. Do you have any results yet for our Fuehrer?"

Werner Heisenberg shrugged. "The technical report is under way. I have no great hopes, as you can imagine. But..." he paused, considering his next words. There were things that no sane man was going to tell to a Party commissioner, ever. And yet...

"You have seen the man's devices. His weapon. That strange gadget he had in a pocket. You know, of course, the conclusions we've arrived at."

"You mean the time-traveler theory. Yes, of course. I understand this is established truth. Which is exactly the reason why we want to know everything possible about the man's devices and technology. His communicator alone could win us the war." said the Commissioner impatiently. "So?"

"Do you realize the effort - the technological effort that must have been necessary for this man to come back here? The energy required? Do you not realize what this has to mean?"

"Explain yourself, Doktor."

"Someone, years in the future - our estimates range from a minimum of one hundred years to a millennium - some large, very powerful entity, like a government, possibly a planetary government, sent back an assassin to kill our Fuehrer. Why would they have done this? Think! What kind of government, what kind of people would want this done?"

"I... don't think I quite see."

The physicist raised his voice. "Don't you see? Time travel must be exceedingly difficult, or we would be up to our ears in time travelers. The man was soft, well fed. He came from a peaceful world... his can not have been a desperate attempt but rather a deliberate, well-researched endeavour. There is only one explanation for this mission to have been allowed, to have been conceived. Why this mission specifically, and not another."

He took a deep breath.

"I could tell you nothing, but the facts are all out, for everyone to see. The story is too big, and it's already too late to silence. The conclusion is logical and inescapable. Somewhere, in the next few years... the Third Reich must have lost. So horribly, so finally, that future generations will not let things stand, but endeavour to wipe us all out from the very history."