2001 XJR Original Tensioners?
 

I am considering the purchase of a 2001 XJR. The VIN falls within the affected range. The car has 143K miles. Is it possible it still has the original plastic tensioners and guides?

The only true way to know if the repair records do not indicate a tensioner/timing chain upgrade is take the cam covers off. One side ought to confirm. 2001 had slightly stronger plastic tensioners but still fallible. If you suspect the parts are original 143K is well past time for an upgrade, change the chains, secondary and primary tensioners for worry free driving. Tons of how-tos on these forums for referral. If you wrench yourself kit and special tools can be had for under 1K. If it does not rattle on startup and has good compression go for if the car is in good shape.