What does the official menu establish?
The official material describes beef patties, burger ingredients and preparation choices. Those facts identify the food; they do not provide a halal certificate. The food-quality page’s reference to USDA ground chuck is a quality description, not evidence of a religious certification.
What has not been verified?
A current certificate identifying a certifier, covered facility, product scope and validity period was not established in the sources reviewed. This is an evidence limitation, not a claim that every supplier and preparation process has been audited.
Supplier sourcing and restaurant preparation are separate questions. Ask for documentation covering the product and preparation that matter to your decision.
Are meat-free choices automatically halal-certified?
No. A Grilled Cheese omits beef, but removing meat does not establish certification of the remaining ingredients or kitchen process. Milkshakes, cheese and sauce have their own ingredient lists.
If certification is required for your decision, ask the company for current written documentation and consult the relevant certifier rather than relying on an internet nickname or an unreferenced assurance.
How to ask a precise sourcing question
Specify the restaurant, the product, the requirement and the date. Ask whether there is a current certificate and which items it covers. Keep ingredient questions distinct from certification questions.
For ingredient declarations, use the allergen guide and the official sources linked below. Return to the in n out menu for item descriptions.