Question

why did Oliver lutkins not reveal his identity at first when the narrator met him for the first time?​

Answer 1

The chapter does not reveal the real motive behind this but the following assumption can be made -

Oliver Lutkins had been ignoring all the letters sent by the law firm so on seeing a well dressed city man he might've become suspicious of his identity . He did not want to take any risk of being identified as he did not wish to be a witness .

there you go :)