The errata sheet listing the known issues in the Esri ArcGIS Desktop Associate Certification Study Guide are posted here.
I can't speak yet to whether or when this book will be updated for 10.3, but even with the 10.3 version of the certification exam coming out, this book is still a valuable study resource. Since the book covers the foundational concepts relevant for the test and is not geared to specific questions, it still helps you to prepare for the majority of the objectives listed Skills Measured section.
We expect the 10.3 version of the exam to be released this summer, before User Conference. There is about a 10% change in functionality between the 10.1 and 10.3 versions that warranted the exam update. Only for the 10% of new, 10.3 specific functionality you'd have to refer to other study resources outside the Study Guide book, such as the online help. Also, the 10.1 version of the exam (there was no exam update at version 10.2) will still be available after the 10.3 exam has been released.
