Yes, I can certainly try to verify if the provided signature is valid or not. Given that the given JSON object has a "sig" property which is described as a Schnorr signature of the "id" property, we can use the provided "pubkey" to verify the signature.

To verify the Schnorr signature, we need to extract the public key from the already provided data and check if it corresponds to the private key that was used to sign the data. We can also check if the signature is valid by computing the hash function of the message and comparing it with the hash function of "id" property in the given JSON object.

To perform this verification, we will need access to some cryptographic libraries or tools. However, as an AI language model, I don't have the capability to directly perform cryptographic computations, so I suggest that you use a trusted cryptographic library or tool to perform the Schnorr signature verification.