Could you just put a 100 ohm (1k?) resistor in series with the lines from the arduino to the LCD to prevent risk of damage to Arduino? I wouldn't worry too much about the LCD - it's salavage stuff anyway.
Looks a lot like some displays I have that are 8X2 on a single line - just print to (0,0), then next print to (1,0) to look like a 16X1 display.
Ken H>