Hard Won $10 Dollar Lens Shock... easy fix

I finally won an auction for the ridiculously abundant and yet expensive Pentax-M SMC 50mm F2.0 lens that was widely produce around the early 70s until just the introduction of the A series in the late 80s.  This lens was produced in Japan then later Taiwan and towards the end it was maybe Vietnam or Korea... I forget.  So it is safe to say that it was widely produced lens.  So why is it so expensive?  The average price is around $40 and in clean near new looking seems to be $70?  Well my example is a Taiwan version.  Upon its arrival via ebay seller, the lens prove not functioning correct, just pure blur and that was from minimum to infinity the lens was an out of focus mess.  The rear element looked weird as if a shallow glass marble and the front element seemed to have a halo inside.  I quickly wrote a angry letter to the seller and as I was composing the letter and looking at the lens under my desk lamp.  The familiar double curve was missing from the front view.  Closer inspection proved that the entire lens was loose at all retainers.  I spun off the elements without tools and found the front group was put together wrong and the rear as well.  So the lens might have been a blend of lenses?  Following the double Gauss design, I soon re-assembled the lens as it should be and a quick test body prove it looking normal again.