Yes, if you have a 3ds with firmware 9.4 you can use the web injection method. As for the 4.3 firmware, like already mentioned you can export your savegame to your sd card using savedatafiler and then edit it using pkhex. The tutorial on gbatemp explains everything on how to install rxtools and FBI on your 3ds which will allow you to install savedatafiler. Updating your firmware to something between 9.0 and 9.5 which will support web injection is harder that installing rxtools and has the risk of bricking your 3ds.