Lycoming's SB569 for Shoppers

Another newbie question for the group:

(I feel like this MUST have been discussed here before, but my search came
up empty--if I need to work on my USENET search skills, try to be gentle
with me....)

Can anyone help me decode what's going on with Lycoming's SB 569? It seems
like all the airplanes I'm looking at use Lycoming IO-540 engines, which I
understand are, possibly, subject to that service bulletin. I've read that
the FAA is considering making that an AD, meaning that the crankshaft would
need to be replaced at the next overhaul or other case opening. There's
something like a three-year window in order to get the new shaft at 2AMU,
after which it will go to 16AMU(?). So--if that's a mandatory replacement,
it seems like there'd be a strong economic argument to overhaul before the
window closes, whether it needs it or not.

- Is there any easy way to tell whether a given airplane has an affected
crankshaft? I'm a newbie, inexperienced (to put it politely) with reading
logs. Of course, I would expect that to turn up in any pre-buy, but I'm
thinking along the lines of maybe there are some other factors that would
let me know "there's no way this plane is affected, because _________"--save
a lot of trouble trying to verify that there's no issue.

- Anyone know the status of the AD? Anyone have opinions on what to do w/
the SB if it does NOT become an AD? I see AOPA is opposed to the AD, for
what that's worth....

- While shopping, any suggestions on how to value/devalue a given airplane
based on its status with this?

Thanks!
--
Doug
"Where am I to go/Now that I've gone too far?" -- Golden Earring, "Twilight
Zone"
(my email is spam-proofed; read the address and make the appropriate change
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