Lois Lowry was deliberately vague about the end of the book. She wanted to leave it up to interpretation for the reader. The short answer is that, no, it is probably not the exact same hill, but it is very similar and Jonas feels he knows it because of the memories, and the way he "knows" it and finds the sled atop it is supposed to add an element of mystery and perhaps even magic to the story's ending. In the last few lines the author tries to communicate that they were going to make it to a better place safely, and although some people theorize that Jonas and Gabriel were freezing to death and reaching heaven, there are two other books in the series which indirectly refer to Jonas. The first is "Gathering Blue", which is about a girl named Kira who lives in a society the opposite of Jonas's: it is primitive and cruel and instead of "releasing" the members deemed inadequate, they send them off to die in the "Field of Leaving" (the same place they leave the bodies of their dead). Near the end of "Gathering Blue" a boy mentions to Kira that in the new society he's found in the woods, there is "a boy with blue eyes" who we can safely assume is Jonas. In the third book, "Messenger", the boy (Matty) is living in the aforementioned society, where their leader, named "Leader" (in this place everyone is given their "true name", a name fitting themselves and who they are; for example, the village schoolteacher is named "Mentor", the wise blind man who can sense things is called "Seer", etc), is described as a young man with blue eyes who came to the society from somewhere far away. Leader is said to have arrived on a red sled, and later he is seen to have the power of "remote viewing" (aka seeing beyond). Leader is, obviously, an older Jonas.
I am a huge fan of the book and have read it (no joke, cover-to-cover) more than eleven times