problem with API gateway OPTIONS > Integration Response step

[seport]

In the tutorials the instruction is to set the Lambda Error Regex to default for the Integration Response for OPTIONS for each operation. However, the Options Integration Response only has a field for HTTP status regex. Is there a typo in the instructions? Did you mean to say set the HTTP status regex to default?

Also, it says to set the Header Mappings Response Header for Access-Control-Allow-Headers to 'Content-Type,Authorization', but when I try to change it to that from the default value of 'Content-Type,Authorization,X-Amz-Date,X-Api-Key,X-Amz-Security-Token' I get the following error:

Invalid mapping expression specified: Validation Result: warnings : [], errors : [Invalid mapping expression parameter specified: method.response.header.Access-Control-Allow-Methods]

is it okay to leave it as the default value?

EDIT: I feel like the above error may actually be due to my having deleted the Access-Control-Allow-Methods method response for the Method Response.... should I have left it in? Or deleted the Application/json response body? I'm a bit confused...