Nowadays, there’s no real need for a single official commentary. It’d be like asking for one official crucifix pattern or one official floor tile. We have dogma and systematic dogmatic theology to keep things straight. So there’s a great deal of freedom interpreting the Bible within those guidelines, which is as it has always been and always should be.
If you read the Catechism or dogmatic theology books, you can find out what a lot of the important key verses are, for various important Catholic concepts and teachings. But even when it comes to those key verses, that doesn’t mean that no other meanings are present. There is layer upon layer of meaning in pretty much every verse of the Bible, so there’s plenty of room to interpret stuff in various ways.
The general attitude has generally been – Go crazy as much as you like with allegorical interpretations of Scripture! As long as you don’t espouse something contrary to morality or the teachings of the Church, it’s okay to interpret it that way. Even if you make a factual mistake, which is quite likely, if you stay within the guidelines it’s not going to send you to Hell. Severe embarrassment is the worst you can suffer.
God uses the Scriptures to speak to all of us individually as well as collectively. So there’s bound to be a lot of individual spiritual experience and insight involved in interpreting the Bible, within the guidelines taught by God through His Church. Therefore, you have to allow people a good chunk of freedom, or risk interfering with the work of the Holy Spirit. If a verse about cows inexplicably causes someone to see an analogy with computers and their work life and thus to repent of doing bad stuff, far be it from the Church to bar that interpretation.