it could potentially work but you'd have to do a lot of extra work with it. I have a set of 2008 Beckers that a co-worker loaned me and the set I bought last year from Becker (2013).
For FAR, the older set does not have the IFRS so you would have to seek another source out for that. One of the most helpful things in 2013 is the appendixes with the charts set up showing the differences between GAAP and FAR. I have heard that IFRS is tested pretty heavily (but I don't know, I don't sit until tomorrow).
For Reg, there are going to be a lot of code updates, so for each concept, you would need to check on the current requirements. I think you could get basics, but that's all I'd risk. Augmenting with a test bank (like Gleim) could make up the deficit.
I have not looked into the Auditing books yet (that's next for me), but I believe the COSO framework was just changed significantly. I would definitely not work with anything older than a current book (Becker allowed 2013 subscribers to order 2014 books for a small fee).
No idea on the BEC section yet. That seems to me that the concepts would be pretty stable.
REG - Nov 4, 2013: 88
FAR - Feb 27, 2014: 86
AUD - April 5, 2014: 91
BEC - May 6, 2014: 83
Florida CPA 24 July 2014
(Done in seven months - thank you Jesus!!)