I recently had to take my SMC 50mm f1.2 apart for fungus on several of the internal elements. It's not difficult, though there is a trick to removing the front element assembly should you need to. Email me for details if you should buy it and need them.

Living in warm, damp south west England, fungus in lenses and on slides is a way of life. As has been said dismantling fixed focal length Pentax lenses isn't too hard, though it sometimes necessitates making up some simple tools. The business of fungus affecting the glass permanently is IMHO much over-stated. I use carbon tetrachloride as both a cleaner and Killer, not forgetting to wipe every part of the lens before reassembly. The price seems pretty excessive for a lens with a known problem, but in view of the extent of the problem as I read it, are you sure it's mould/fungus and not coffee/beer/Coke that someone's spilled on it?