The ESD protection are needed for pin 1 (VDD I/O) and pin 6 (VS) on ADXL345.
Just any ESD diode would work and serve the purpose of protection. The current
ADXL345 sample you have on hand, plus the any ADXL345 we ship to you before
August(2008), will need ESD protection. After August, the new ADXL345 will
have ESD issue fixed.