The object database was a flat file in R77.x and was changed to a proper database in R80.
Although we didn't expose the "last modified" information in the UI, it was tracked, both in the audit logs and in the object itself.
For example:
: (Net_192.168.1.0
:AdminInfo (
:chkpf_uid ("{CD4CE7E8-801B-480D-BEFD-079527BC0024}")
:ClassName (network)
:table (network_objects)
:Wiznum (-1)
:LastModified (
:Time ("Thu May 28 21:18:04 2015")
:last_modified_utc (1432847884)
:By (phoneboy)
:From (bunsen)
)
:icon ("NetworkObjects/Network/Network")
:name (Net_192.168.1.0)
)
And, after I upgrade to R80.20, I can see that information is lost in the object:
So you are correct.
That said, from what I can tell, on a going forward basis from R80, this information should be preserved.
It's only in the migration from R77.x that the information gets lost.
I'm not sure what the technical reason is for not preserving that.