If it's got 5 modes it's almost certainly regulated.
How long does it run for ?
Does it dim or stay bright to the bitter end ?
The light just slowly drops down, it seems like direct drive to me. The 5-modes are just created by PWM I think. I don't even know if it's possible to easily make an 18650 P7 light regulated since a fully charged 18650 will push over 2.8 amps briefly and then less as it drops so a simple boost or buck setup wouldn't work.