Yes it is possible to restore your baseband and IMEI number without using any box like Z3X. You can follow the following steps to restore your baseband and I ME I number. Before flashing your smartphone you need to download Samsung from there for your origin country just support your origin country is India than you have to download Indian from here only, because many countries locked dear network for a particular country.'   While flashing your Samsung phone with Samsung Odin you need to make your PHONE EFS clear and phone bootloader update or checked then connect your Samsung device ( download mode ) with Samsung Odin and click on flash button it will flash your device. (In case your device did not appear in Samsung Odin3 then install Samsung USB driver). In case the Odin failed to flash Samsung Device or show you error like Please get the approval to use factory binary (Pit) .You can also fix it. you need to select extra setting on Odin and then tick on Nand flash. It will fix the error temporarily. If you have installed TWRP, go to my manager and delete everything inside the EFS folder and now you don't need the original stock ROM just download APDN or APDU but it will required binary file.