Welcome to the forums! Closing the L2 bridges (if done correctly) will unlock the extra cache on applebreds that aren't superlocked. Can you change the multiplier? If so, you can get the extra cache to unlock. If your board doesn't support multiplier adjustments, post the info on the black sticker-thing on your cpu, including the OPN, "stepping," and week (the week will probably tell us if it's superlocked or not).
There is, however, a chance that the cache will be bad or non-fuctional, in which case you'll just have to undo the mod. There is also risk that goes along with playing with your cpu. Make sure you connect the proper brides in the proper manner, don't shortanything, and watch out for static discharge.