bikeamtn,
Yes, you can use the i436. However, the i436 is still subject to the high pass filter that Apple applies to the headset mic input of iOS devices (even Macs with headset support apply a filter). Frequency response plots of the filter can be found on our blog.
You can just enter the sensitivity of the mic in mV/Pa to get accurate readings (except at frequencies affected by the filter), although a proper calibration is still generally recommended.
Ben