They are reprinted signatures. Innuendo was released with a number of original genuine signatures on posters of 2 different sizes for promotion- only a handful of those were released and they were signed by the band. Loads more were forged by the queen fan club on albums, posters and singles. Then you have these- reprinted signatures. The band didn't touch this item.
Indeed this is a collectable item for the Queen records collectors; it's the only case that stamped signatures were used for promoting a Queen LP. About 100 copies of the Innuendo LP were sent to publicists and records executives. Unusual signatures but originally genuine. Actually they are very delicate and tend to fading so surely made with a stamp.