Hair transplant - Will 800 grafts (400 each side) be enough for my hairline? (Photos)

From the photos it appears that a conservative reinforcement and lowering of the hairline can be accomplished.  Other factors to consider with a hair transplant to the hairline are your age and the progression of hair loss.  It appears that your hairline is higher on the right than on the left side.  800 grafts may be appropriate or maybe fewer depending on the actual placement of the hairline.  

Whether 800 grafts are enough for your hairline depends on your hair transplant goal. If you want a more aggressive hairline with advanced temple points, then you may need additional grafts. This is something that can be discussed in an initial consultation with a hair restoration surgeon.
It is also important to consider where these grafts will come from—the traditional donor area on the back of the head can provide between 5-7 thousand grafts, but exhausting these too quickly can be a problem when addressing future hair loss. Hair from this donor area also tends to grow thicker than that which grows on the hairline, which can result in harsh looking hairline reconstructions.
These reasons are, in part, why I designed the FUE Shave Test. Using this test, I can determine if a patient qualifies for a nape hair transplant, or if their hair loss will progress into a severely bald (Norwood 7) stage.
Visit the link below to learn more about young age hair hairline reconstruction.

Photos cannot determine if you would be a good candidate for surgery.  You need an examination and the doctor needs to understand your goals and expectations.

The hairline requirement will depend on the level at which you want the hairline to be made and the density expected by you.Although 800 grafts look to be sufficient for a normal density but if you want more density, then the number of grafts should be increased.

This is a decision between you and your doctor. He/she will take into account the various factors that determine the correct estimate. 400 grafts looks a bit small for good densities.