When I did mine I thought there had been the same mistake but turned out it wasn't.
I ordered the chain I wanted from M and P as a kit as it was on a special deal which was cheaper than anywhere else including sprockets.
https://www.tiger800.co.uk/index.php/topic,24021.0.htmlHowever the rear sprocket was an unmarked make and the supplied front JT one non-cush drive.
I had already decided on JT sprockets and bought them (cush front) elsewhere. As mentioned in the above link due to an incorrectly supplied chain splitter I negotiated a free spare front sprocket. All 3 supplied front sprockets were/are 520.16 size and the cush one looks bigger but isn't and matched the removed factory sprocket.
Spares - The non-cush (from M and P) and the cush - both 520.

JTs catalogue lists the 520 front, 525 rear and 525 chain for Tiger 800 .... probably designed to allow for better tolerance on sprocket misalignment and wear.
http://www.jtsprockets.com/catalogue/model/s5538/