I know the version you are talking about. I had the same disappointment.
The Armenians do have Maccabees 1-3. I think the 4th Maccabees is considered pious reading, but is not exactly scripture. Ghazaros may know more about this than I do. I know we consider the Septuagint to be the correct Old Testament.
I think what happened with the particular Bible you are talking about is that to save money, the Eastern Diocese just got a Catholic Bible and added an Armenian cover, articles, etc.-Again, Ghazaros may know more of the story than I do.
The only English Bible that I know of that has the complete canon of Scripture is the Oxford Annotated, which you mentioned. I look forward to the Antiochian Church's Orthodox Study Bible, which is supposed to come out in a couple of years. I think that will also have the complete canon, hopefully with all the books in the correct order.