Reading LCD Register bits on AtMega169pv w/Arduino

I am trying to use an Arduino Duemilanove to read the LCD register bits of an AtMega169pv. The 169pv I am trying to interface with is in a commercially produced device. I can not reprogram it, but I do have access to the SPI interface pins through test pads on the circuit board. I am trying to read what the device sends to the LCD screen. From the datasheet, I can see that the LCD segments are written to registers 0xEC – 0xFE. If I can interface this device to the Arduino, I can data log the screen information directly from the registers. I have searched the web and forums for similar applications. I can find a lot on writing and reading to eeproms or other slave devices, but not to another AtMega. The Atmel site has an application page on SPI between to controllers, but they write code directly to each controller to set one as master and the other as slave. I am new to microcontrollers, so I am not sure if it is possible to send opcodes through the SPI to initiate the slave and read the register without directly programming the slave.

Is it possible for the Arduino to read the registers without first uploading a program to the slave 169pv?

If it is possible, can anyone help me with the opcodes and a sample sketch?