Xperia10 after installation bootloader unlock or lock

after end the installation of sailfish in xperia 10, bootloader is unlocked, is more safely if i locking it , how can looking it?

you cannot have at the same time SFOS and a bootloader locked. And afaik, after unlocking the bootloader, there is no way to relock the bootloader (at least on X10).
See for example

ok. thank you