Getting a used L lens in long-term production

[Marsu42]

I'd like to purchase a used 17-40L because I need some uwa for ff (group portraits in close quarters & some landscape). It might not see much use since I'll most likely get the Canon 24-70/2.8ii for most shots, so I'd like to save some $$$ on the uwa. And the 17-40L will do on my 60d if I don't want to walk around with €4000-€5000 gear.

Question: The 17-40L is in production for a long time, do you think a newer sample has an advantage over an older one because there were some optimizations in the production? I'm puzzled because most offers are rather expensive (80% of new) and they're all in "good condition" yadayadayada... so if you have any other hints please feel free to share :-)

[neuroanatomist]

I don't believe Canon does 'stealth' updates.   Heck, when they updated the 18-55 and 55-250 kit lenses with a couple of cosmetic changes to make production a tiny bit cheaper, they announced them as MkII versions.  They do correct problems without an update, for example the 'rays of light' flare on the 24-105L that was fixed with the UT11xx and following production runs (and older lenses could be sent in). 

Of course, the longer a lens has been in service, the more likely something is wearing out, or has worn out, or internal damage (e.g., decentering) has occurred.

In 2010, I bought a 200/2.8L II with a UL date code (1997, second year for that lens and six years before the 17-40L was even released).  It was optically and mechanically excellent (and a great deal at $450!).  I sold it only after getting the 70-200/2.8L IS II.

The key is to test the lens thoroughly.

[Marsu42]

I don't believe Canon does 'stealth' updates.

Not the hardware itself, but they might have ironed out some production variances (like more or less sharp corners) - the idea came to me when the discussion was if the 24-70 mk1 was sharp @f2.8 or not and some people said they couldn't be happier with recently produced samples.

But obviously nothing specific is known about the 17-40 so I'll just ignore the production date - thanks!