Is there a way to launch game discs region free using PSBBN?

Hey all, so I am planning on getting a fat Japanese PS2 soon and I would like to install PSBBN and maybe mainly use HDD OSD but I do have official Japanese and US discs that I want to play from the disc drive as well. Is there a way to do it without a mod chip? And if so what PS2 revision should I go for? I can't find a US PS2 where I live currently.