it would be wise to clean all surfaces that has any oil leak residue. Make sure the leak is complete clean. Recheck and confirm that the leak is not oil residue from oil filter removal and or rear main engine oil seal. It is very rare to have the number one oil pan to leak on those model. If it did not leak for soo many miles it is unlikely to have the number one oil pan leak because of how they seal those in the factory.
Thanks for letting me know that the upper pan is designated as number one oil pan. I am absoulutely sure that the leakage is from this pan. We had it up on a lift and with the engine running. Oil was squorting out in front of my eyes. I am disappointed by Lexus that they choose to seal it with a silcone. I will call Lexus tomorrow and will hear what they have to say.