Is it possible to load or search bundles by script ? What is their record type ?

I don't think the 'Installed from Bundle' field is there on Script page, so not a way to search for them. However if you don't want to perform any operations on them, and just wish to inspect the scripts which were installed from bundles, just visit https://system.netsuite.com/app/common/scripting/scriptlist.nl and sort by 'From Bundle' column. Also, bundle records are not load-able/edit-able or so I think.