How to tell when a part was created.
Solution
1. With the part set as the displayed part, select 'Edit-->Properties'.
2. Select the 'Part File' tab.
This will list the creation date and time.
Notes and References
Hardware/Software Configuration
Platform: all
OS: n/a
OS Version: n/a
Product: NX
Application: ASSEMBLIES
Version: V8.5
Function: ASSEMBLY_MODEL
Ref: 001-7200969