So, 45 deg and more is flat.
Ah okay, if that's how we're defining it. My experience spinning Cessnas has shown that they will sometimes bob up and down a bit, so there might be elements of both flat and normal by that definition.
That said, however, and with deference to BPF's remarks, a 152 Aerobat will spin about the same per C of G position - it does not have skeletons in its closet. Thus I prefer just say we're going to spin, and leave the drama terms aside. For my experience, the term "flat spin" suggests a real problem getting the nose down to recover, and thus an alarmingly delayed recovery.
I have only experienced this once, while spin testing a modified Cessna Grand Caravan, loaded to gross weight, and the aft C of G limit. It did come out within the design requirements, but that one turn in, and second turn out were very un-nerving, as to the delay in response to full nose down elevator applied and held. This was dramaically different from the characteristics I had observed in that aircraft the day before loaded gross weight full forward C of G. Thus, I was reminded that the aft C of G limit is determined by spin recovery characteristics, and not to exceed load limits.
That all said, in my opinion, Aerobats spin. Spinning beyond a turn or two is a wasteful and needlessly dangerous activity, and safely spinning them requires a recovery to be complete at an altitude greater than 1000 feet AGL