Checkerrr As @trashaccount said before, it doesn't matter.
From https://grapheneos.org/install/web#verifying-installation:
The verified boot and attestation features provided by the supported devices can be used to verify that the hardware, firmware and GrapheneOS installation are genuine. Even if the computer you used to flash GrapheneOS was compromised and an attacker replaced GrapheneOS with their own malicious OS, it can be detected with these features.
Verified boot verifies the entirety of the firmware and OS images on every boot. The public key for the firmware images is burned into fuses in the SoC at the factory. Firmware security updates also update the rollback index burned into fuses to provide rollback protection.
The final firmware boot stage before the OS is responsible for verifying it. For the stock OS, it uses a hard-wired public key. Installing GrapheneOS flashes the GrapheneOS verified boot public key to the secure element. Each boot, this key is loaded and used to verify the OS. For both the stock OS and GrapheneOS, a rollback index based on the security patch level is loaded from the secure element to provide rollback protection.
Please read the documentation thoroughly next time as your question was already answered by it.
TLDR: Check the verified boot key hash matches and conduct an Auditor check. If both of these pass, your installation is genuine.