Posted By:
WesleyBoth SGC and PSA will grade your proof cards. I have seen E97 B & W cards in both PSA and SGC holders.
As far as a more modern example, I owned a 1967 Topps Standup proof card that was handcut from a factory sheet. It was obvious that the sheet was not cut by Topps and my card in particular had a very wavy and slanted cut. I submitted the card to PSA who refused to grade the card citing evidence of trimming. The card was then sent to SGC who encapsulated it and did not identify as a proof.
The weird thing is that other 1967 Standup cards from the exact same sheet made their way into PSA holders. Maybe the edges on those cards had less of an irregular cut than mine.