Is every PCGS slabbed coin now an "upgrade candidate?"

I remember a few years ago every rattler on ebay was called an "upgrade candidate;" will this now happen for all non-Secure + holdered coins?
"It's far easier to fight for principles, than to live up to them." Adlai Stevenson
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Assuming every coin with a + rating is actually a .7/.8/.9 then there is a reasonably strong probability that the majority of those can eventually be upgraded at one or another TPG. It's just a matter of how many times you can afford to send it in. Whereas the rattler coins have been pretty well picked over in the market place, the + coins will be fresh meat. Based on past experience I'd say the vast majority of .7 to .9 coins were eventually upgraded at one grading service or another.
roadrunner