No, once you give the permission via chmod, this should be fine. What permissions to set should be explained in the installation process. But those permission need to be set on the server, the chmod has to do with the linux server, and only indirectly with LS.
You also should be conservative with the permissions and only modify them where necessary - thus I would leave everything as it is, as long as you don't run into a problem.
Following the installation instructions, you should be fine (of course this also depends on the configuration of your server):
docs.limesurvey.org/tiki-index.php?page=...irectory_permissions