How many poles does the TB-303 filter have?

The VCF in the Roland TB-303 is nearly always described as being a 3-pole (18 dB/octave) filter. Many 303 aficianados claim that this is one of the things that gives the 303 its unique sound. However, Tim Stinchome says it's a 4-pole filter. And he's got the math and the SPICE simulations to prove it.