Unless you have any reason to do it, I wouldn't. We all know the bottom ends are near damn bulletproof. I would recommend you rebuild the head though. At 200k the guides + seals will be toast, your valves need to be replaced or lapped, and everything cleaned and skimmed.
Looks like a ton of carbon buildup on those pistons too -- get a dremel with a cleaning attachment and carefully get rid of that (TDC piston of course)
Whats that green crap too
Drain the block, flush everything and get Zerex G05 in there.