mongodb - Do we need to delete the collection named system.indexes to make new indexes apply on the collection -

i have question indexes in mongodb.

i using mongodb version 1.6.5. modifying collection indexes.

when used show collections command in mongodb shell, showed 1 of collections

system.indexes stocks options 

do need drop collection system.indexes make new indexes on collections apply?

thew system.profile collection not there however, no not. profile collection output of profiler, nothing more. indexes still apply.

edit

since question says 2 things, no not need drop system.indexes either, mongodb handle updating records in there you. dropping might damage database.