I'm a little confused (doesn't take much tbf..)
I have SLX on the Hardtail and XT on the FS.
How come the pads for the SLX are marked up as XTR, they've got a hook at one end and a hole at the other for the pin, and pads I have marked as SLX/XT have the mounting hole in the middle so clearly don't fit!
hooked ones are the older shape. only on deore now.
hook at one end/ hole at the other are old style and would be common to old XT & SLX (XT model number was M775)
hole in the middle is current (2012 models onwards I think) and again is common to current XT & SLX (XT model number is M785)
The brakes you have are different versions, the SLX will be the original M665brakes and not the newer M666/675 version which have the hole in the middle.
You can get different level pads to fit any brake from the same range, ie M980/985, M785, M666/675