For a standard, non-BLS ZOLL AED 3, yes, no software update is required. For a ZOLL AED 3 BLS configuration specifically, CPR Uni-Padz III is approved only on software revision 06.03.006 or later, per ZOLL's own product documentation. If your unit is a BLS configuration running an older software revision, it is not a confirmed match for this pad without first updating the unit's software.
If you are not sure whether your AED 3 is a standard or BLS configuration, or do not know your unit's current software revision, call Total AEDs at (855) 286-6384 before ordering. Confirming this by phone takes a few minutes and avoids a mismatch between your unit's software and the pads you receive.