It's likely the chip is programed like a PROM. You should find the datasheet (http://datasheet.elcodis.com/pdf2/75/52/755267/pal16l8bcn.pdf
) and see if i has a read/verify process. Shouldn't be hard to program the Arduino to read back the programming.
The 16L8 has 10 inputs and 8 outputs. All models have a 32x64 programmable AND array.
After programming and verification, a PAL16R8 Family design can be secured by programming the security fuse. Once programmed, this fuse defeats readback of the internal programmed pattern by a device program- mer, securing proprietary designs from competitors. When the security fuse is programmed, the array will read as if every fuse is programmed."
That means you may not be able to directly read the contents. You could step through all possible patterns of inputs to get the truth table and reverse-engineer the fuses from there.