Probably a no go. The original panniers of the XL600V Transalp where made by Hebco & Becker and a-symetrical due to the one side exhaust muffler; where the panniers from the MK1 Varadero where symetrical (double exhaust mufflers).
I would suggest an after marked pannierset which are interchangeable. You only need to buy a new rack if you change bike. There are good alternatives, even used.