After waking-up, how do you know if your mac was hibernating (fully powered off like Windows PC) and not sleeping?
When you wake a Mac from hibernation, RAM got written to disk and power removed from memory. Then, at wake, it gets read back into RAM.  This takes longer than normal, or standby sleep (depending on the delay set) and is visible at wake time by showing an Apple symbol and progress bar underneath (white time markers filling up).
Also running the following command in Terminal:

pmset -g log | grep -i "wake from"


will show the sleep states, e.g. 


  Wake from Hibernate 
  Wake from Normal Sleep 
  Wake from Standby


The last time I saw the 'Deepsleep' widget in action, it did the same as hibernation, i.e. write to disk and remove power from memory.
PS.
As the man pages (man pmset) hint in the quote below, standby and autopoweroff should be set to the value "0", via the same pmset command you've used to set hibernatemode, to set your MacBook Pro to use hibernation instead of normal, or standby sleep (I would also disable any Energy Saver System Preferences to wake your Mac periodically): 


  For example, on desktops that support standby a hibernation image
  will be written after the specified standbydelay time. To disable
  hibernation images completely, ensure hibernatemode standby and
  autopoweroff are all set to 0.


PPS.  But please also consider the following thread here on AskDifferent:
How to add hibernate mode to MacBook Pro