How to compare objects across libraries to ensure they came from the same source.

I want to compare files and programs in various libraries on an IBM i5 to make sure they all came from the same source compiled at the same time.  For instance, if I compiled my file on a development machine and then moved it to another machine into different libraries, how can I check to make sure they were all compiled at the same time from the same source?  The problem our shop is facing is that developers do not always remember to copy the objects they've installed into production into other libraries which emulate production.  The file structures should be the same even if the data in one comes from production and the data in the others are a subset of productions.  Likewise, I need to check programs for the same reasons.  I ran the DSPOBJD command on a file in various libraries and although they may have the same creation date, the file levels are different for all of them when I run the DSPFD command.  I would have expected them to be  the same if they were compiled around the same time using the same source.  Am I doing something wrong or is my logic faulty using the file level and creation date?

Thank you!