[ls7plus]

Yes, a card most definitively can be trimmed, yet measure full-size. In my area, when PSA was just getting started, there was one dealer who specialized in turning off-grade '50's and '60's cards into near mint/mint. From what I later read, the cards would be put through a paper press, slightly expanding their size, then carefully trimmed back down to size, removing worn corners and/or edges in the process. When grading took hold, the grading services pretty much eliminated this tactic.

The key is to use a loupe (I have a 16x loupe) or high-powered magnifying glass to examine the edges. If the edges display a rough cut, the card is most likely virgin and untouched. If they are wire sharp, however, the card will be rejected by the grading services as trimmed, despite the fact that they meet the standard size. Also, if the edges appear rough but seem to be pinched at the corners, the card will be rejected. I learned the hard way, by submitting what appeared to be true NMt/Mt cards to PSA, only to have them labeled trimmed.

Hopes this helps,

Larry