Welcome and congratulations!
As for the door lock cap, you'll have to call Bavarian Autosport. Their number is 800.535.2002 ext. 5 for BMW sales and service. I cannot find the part on the Pelican Parts 2001 740iL Page
So I think your best bet will be to call BavAuto. They claim to have every part for every car. And in some cases, a special order part from the dealer or from other places will not be a special order part there.
Best of luck with your new BMW!