Would the implants need to be custom to fix the asymmetry? (Photos)

Firstly, I think it would be important that you appreciate the asymmetry of the features of people you admire.
In the front view reference photograph, the right eye and cheek bone are higher than the left and the chin point on the left side is lower. The corner of the mouth is also higher on the right side and the right ear is positioned higher than the left.
Nonetheless, this does not stop any of us from appreciating  the aesthetics of his facial features. In this respect, it is I believe important that to appreciate  that our perceptions seem to have a priority mechanism, and symmetry is not necessarily at the top of the list.
In your case, adjustment in the contour of the neck through a short scar neck lift or anterior neck lift intervention can help reduce the girth of the neck and deepen the angle between the underside of the chin and neck. This already makes the chin appear more prominent.
A chin implant whether custom-made or off-the-shelf, typically still require some adjustments to produce a result close to the preplanned external appearance. In your case, this would be a squarer contour of the chin which helps the impression that the side of the jaw is straight rather than slightly convex.
An additional feature in the reference photographs is the more sunken appearance of the cheeks. Buccal fat reduction can assist with this change.
Angle of the jaw implant can also help, but it would be safer to evaluate in a 3D imaging and simulation whether you really feel they contribute to your features.

The price of Chin Implant operation depends on several factors such as the difficulty of your case and your request for your operation area.
In my practice, prices for Chin Implant operation reaches from 2250 Euro up to 2450 Euro range, and it also includes the travel package such as accommodation, local transfers, and language assistance. If you want to learn more you can click the link below.

To simultaneously augment the entire jawline as well as improve any asymmetries, a custom jawline implant approach is the only effective method. Made from the patient's 3D CT scan a jawline implant is designed from one angle to the other angle. Such designs incorporate any correction of bony asymmetries that exist between the two sides of the jawline.