The problem with using most technologies to authenticate cards and detect alterations, is that you also need the baseline information to compare to.
A card that's pressed and trimmed will be thinner, or thinner in the pressed areas. And measuring thickness is pretty easy, even without modern technology.
But the question becomes "what thickness should that card be, and how much could that naturally vary based on the papermaking technology at the time. in the 1880's (where I've seen studies of printed items specifically looking at the paper thickness of hundreds of copies) +/- .003 isn't unreasonable.
That spec may be a bit tighter by 1910, and should be much tighter for modern cards. I just measured a handful of modern cards - list on the postwar side - and didn't find much variation at all.
Other groups have studied the chemical makeup of the inks and seizing(sp?) of the paper. The equipment used is expensive, and requires a bit of interpretation of the results, but some interesting things have been learned.
As far as I know, there isn't anyone who has studied this stuff for cards. If it's in a database, I don't think it's been publicly available.
There also isn't one for any of the other things that would be of interest, like UV reaction. The only bit I know is out there is that the 1991 Topps backs have two different inks, one reactive the other not. Other Topps sets in the junk wax era also have the same issue, which I mentioned once, but haven't pursued yet, not even as far as dividing my sets. I collect a lot more that isn't really cataloged or known anywhere. (And yes, I really need to do at least a few posts on those)
If it isn't know exactly what a normal card should be, no entirely reliable comparison can be made.
Currently, someone with experience can tell. After years you get a feel for when something just isn't "right". But to have a machine do that you have to give it the knowledge.
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