No, and for a very straightforward reason: Hardened Scales requires that at least one counter be placed on the creature before it adds any additional counters:
The key text here is 'If one or more'. You're trying to put zero counters on the Hangarback Walker, and so Hardened Scales never processes.
Casting Hangarback Walker for 0, and it will enter the battlefield with zero +1/+1 counters. Since Hardened Scales requires "one or more" +1/+1 counters to be put on the permanent to trigger the replacement effect, Hardened Scales won't trigger. Hangarback Walker will Enter the Battlefield as a 0/0, and die due to state based Actions.
If you want to play Hangarback Walker for free, there are options:
Have a permanent in play that provides an anthem effect to your creatures of at least +0/+1.
Graft is not an option. Though the triggered effect of the creature will happen, state based actions will kill the 0/0 Hangarback Walker before the trigger can be placed on the stack.
I would just like to add to Steven Stadnicki's answer that even if it was a triggered ability that put counters on creatures when they enter the battlefield it still will not work.
State base actions would see a creature with zero toughness and it would be put in the graveyard before the triggered ability gets a chance to put any counters on it.
So lets say for instance instead of the scales you had Aquastrand Spider it still would not work for the reason I stated.