Could I add data with my own timestamps?

[Gutsycat]

So I got bunch of data (log file) with it's timestamp included for each item ex:

02-04-2017 12:02:45 message: 123
02-05-2017 13:32:21 message: 313

but todat it's 17-12-2018 could I add this data with timestamps like

my timestamp 02-04-2017 12:02:45 data 123.12
my timestamp 02-05-2017 13:32:21 data 313.45