From the site:

Directing portions of proceeds to Luigi’s GiveSendgo defense fund

our products are not officially endorsed by Luigi Mangione, his representatives, or any associated entities.

So no, it’s not official.

They have some photos of donation receipts but there’s no amount, I haven’t made the effort to see if the IDs on them can be publicly traced to that.

Nowhere on the website does it say what portion of proceeds are donated.