Thanks, I was following a tutorial that mentioned using the move_toward() method to accelerate and decelerate. I did some testing by forcing my game down to 10 fps and the acceleration and deceleration were significantly different, so I guess that answers my question.
I ended up changing the function I used, because that one, when applying delta to friction and acceleration, made me have huge acceleration and friction numbers.
These are the key parts of my final code:
const speed : int = 500
const acceleration : float = 3.0
const friction : float = 7.5
## With in the _physics_process function
velocity = lerp(velocity, direction * speed, acceleration * delta)
# For stopping
velocity = lerp(velocity, Vector2.ZERO, friction * delta)
# And then...
velocity = move_and_slide(velocity)
Testing out my game in different frame rates showed significant changes in acceleration and friction if delta was not applied. So you do have to apply delta to acceleration and friction if your setup is like mine.