I need to know when some Macbook did run first time. Is it possible?
I would choose
stat -x /var/db/.AppleSetupDone to look at file creation dates in conjunction with estimating the build date of your Mac.
Enter the serial number of your Mac here or here to get the build week and year. To get the serial number enter
system_profiler SPHardwareDataType |grep "Serial Number (system)" or use About this Mac -> System Profile
If the timespan is small between both dates it's quite likely that the Mac was booted for the first time just before the file .AppleSetupDone was created.
My Mac has the build date "Week 14, 2011" and the file creation date of .AppleSetupDone is "Jun 13 21:45:11 2012". It's obvious that I erased the Mac on Jun, 13 2012 and reinstalled a new system.