How to check request as result of 301

Not generally possible. A 30x redirect results in an atomically new request to the stated resource. The only other potentially useful information might be a Referer header, but that's not consistent. If you have control of the service generating the redirect, and the destination service is in the same domain, you could potentially drop a cookie in the redirect and pick it up in the next new request. There might also be a client side JavaScript option, but not 100% certain.