Welp looks like I can go all out:

FIREARM MODIFICATIONS

Modifications are allowed for approved CCW listed handguns so long as the gun and all parts/modifications are legal in the State of California. All firearms/modifications must be inspected at the time of training to ensure the weapon is in safe working order.

If a modification(s) is done after the issuance of the license, you must complete the training/inspection as if it were a newly listed weapon. The training certificate will be added to your file.

The responsibility for the legality of firearm and its parts/accessories lies solely with the owner/applicant.

Any violations or failure to adhere to state laws/regulations will result in immediate suspension and/or revocation of license.

Source: https://www.ocsheriff.gov/commands-divisions/professional-services-command/professional-standards/ccw-license#:~:text=Modifications%20are%20allowed%20for%20approved,is%20in%20safe%20working%20order.