It should Mount Up fairly simple as the Frame designs are really not that different the Issue could Be the fender deck on the Signature series I Know the 40 loader will mount to the Previous X400 thru X748 Back In the day I Looked at Buying a X465 due to the 45 Loader sub frame Interfering with cooling the air cooled engine . Deere at the time Told me the 40 loader would Mount right on the The X465. The frame design for the Signature series is Based On the Previous X465 thru X749 design 