Can I put the Acknowledgments at the end of the book instead of the front?

Yes, from version 1.9.15. Open the book and go to "Include in book" in the Export card. The list has a "Chapters" line between the front matter and the back matter. Drag "Acknowledgments" below that line, or click its down arrow until it crosses it; then place it where you want, for example after the Epilogue, as novels usually have it. The Author's Note can be moved the same way. Other sections stay on their own side: a Prologue after the chapters or a Glossary before them would not make sense.