Saturn controllers with 4539BF instead of a 74153

[Blaine]

Looking over a broken Saturn controller that I'm planning on harvesting for parts, I noticed this one (3rd party) was using two 4539BF ICs instead of the 74153.

Does anyone know where I can find a datasheet on these? Or are they simply 74153s?

Thanks.

[kendrick]

Datasheet here. Part number is a little off, but it's the same chip:

http://www.semiconductors.philips.com/acrobat/datasheets/HEF4539B_CNV_3.pdf

[Blaine]

Thank you.