If you want to be more catholic than the pope, then you'll run the calibration procedure.
The calibration is for the ECU to learn the end stops of the flap travel.
Otherwise, the mechanical tolerances between two different bodies could lead to the ECU to use the old values and drive the new flap motor past its new end point and therefore shorten its life.
Yes, it will apparently work without any procedure, but for sure JLR guys didn't put the procedure there without a reason.
If you want an analogy, it's like using other than normal TR modes on dry tarmac. It will work OK, but in the long run it may shorten the drivetrain components life.
On the other hand, you can be lucky and have two different throttle bodies with the same stop values.
So, for a guy that doesn't have access to a dealer tool, then yes, it can be used without any calibration.
But if you have the opportunity to calibrate it, then by all means, do it when you change it.

Just an update.
Ordered the part from Duckworth's and replaced it myself. It took about an hour. Done about 300mls. so far no problems.
I dismantled the old body to see what had failed. The plastic gears had stripped.
Some of the older members of the forum, like myself, may remember the Twin Tub washing machine which just lasted for ever. So they put plastic cogs in the gear box, problem solved.
I now await my next problem/breakdown.
Regards Paul