I know that the NTSC model Sony brand PSOne LCD screen can be used to display any compatible RGB input signal directly from the Sony AV Multi connector if you make a female RGB-21 to male AV Multi adapter like I did
I've even tested it with the Sega Master System and N64 via an RGB amp circuit I made. It will display 240P and 480i NTSC signals for sure. Therefore, you CAN use the LCD as a display for any version of the older NTSC PlayStations (1, 2, 3) HOWEVER, the LCD screen won't be able to directly mount to the back of anything besides the PSOne.