Would these be recently acquired PX10's? I suspect in terms of pure monetary value, you should leave everything as is unless it is broken or missing and then of course replace with the appropriate part. Myself,I would never be that picky. I like to ride my bikes so fresh cables/housing/brake pads/tubes/tires/chain/freewheel and probably brake hoods would be an improvement as far as I'm concerned. As somebody mentioned, you can always keep the old stuff in a box for show if that's important. I'm one of those inbetweeners that iab referred to. Not point in keeping it 100% original 'cause it wouldn't be ridable and no point in a perfect restoration 'cause it won't stay that way once I start riding it.