I would treat these coins as raw and use your own judgement.
I would go even farther, and say that any coin which "ought" to be in a holder from one of the companies named by SeatedNut, yet isn't, should be avoided unless you really know your stuff.
I'm not talking about mid-MS Morgans or EF Large Cents, which are plentiful. I mean coins like Seated Dollars, AU and above Bust Halfs, any gold, and the like. The people creating these basement slabs are immoral, not ignorant. They know darn well that a PCGS
MS64 will earn them a lot more money than a TSG MS68. The coin would be in a PCGS
slab if it could get into one.
As a rough guess, you can assume that a "TSG" MS65 coin is probably not even Uncirculated.
That doesn't mean you should completely shy away from basement slabs. If the photos are good (few are), and you're a variety collector like me, then there are, um, deals to be had. Nothing feels as good as snagging a valuable VAM
from a third-world slabber who doesn't know what he's got.
The best thing about a bicycle is that it uses no gasoline, therefore the chance of fiery death is greatly reduced.
First Catman, then Gary Burke and now Bigg Fredd - there's one heck of a coin club in Heaven.