There seems no doubt that they could drive them significantly louder than you'd ever conceivably want or need, but I suggest you hunt for reviews to see how they stand up subjectively.
There's one little thing about Beyer headphones, though - their own amp (the A1) has an output impedance of 100 ohms, and when I contacted Beyer about this, they said they generally test their headphones with a 120 ohm output impedance, per some standard. The NFB-12 has an output impedance of 2 ohms, so the frequency response may not be exactly the same as what the Beyer engineers aimed for. HOWEVER, if that is true (and I'm not even 100% sure it is true), you could easily fix that by adding some impedance on the output of the NFB-12. What you don't want is an amp with a high impedance, because there's nothing you can do to reduce it. Knowing that the Beyer A1 amp has an impedance of 100 ohms, I just don't think I'd ever consider it - it's optimised for their own headphones only.
Greg.