Filter Design for Charge Output Transducer (accelerometer)
Protect your signal integrity by capturing the charge on the feedback cap as early as you can.  I suggest the charge amp first and then the low pass filter afterward. The charge amplifier is an integrator, and constitutes somewhat of a low pass filter all by itself.

I've never seen anything between the piezo element and the amplifier in any application note I've ever seen. 

If you must filter, filter later, unless you can think of a very solid reason why you need to do otherwise