These are the CPUs listed for sale with that model. Using any of those should be safe, although there may be different revisions of the motherboards they used with them. Really the only way to know if you are seeing different reports of it working or not is to try it. Make sure you get the latest BIOS for your model first.
Premiere performance and ultraportability; two spindles
Available processors are:
Intel® Core™ i3-2350M processor (dual-core, 2.30GHz, 3MB Cache),
Intel Core i5-2450M processor (dual-core, 2.50GHz, 3MB Cache),
Intel® Core™ i5-3210M processor (dual-core, 2.50GHz, 3MB Cache),
Intel Core i7-3612QM processor (quad-core, 2.10GHz, 6MB Cache),
Intel® Celeron® Processor B815 (dual core, 1.60 GHz, 2M Cache)