I've had the exact same thing happen to me this past month. I bought a lot of 55 Bowman off the guy who opened them in packs back in 55. I posted here on net54 this purchase a year ago as it was a fun buy...the original owner wrote the numbers in ink on the front of most of the cards. I submitted the Mantle and the Mays just to get them slabbed (love the SGC look for 50s cards) and honestly, just like you, really didn't care about the grade. Plus the cards aren't going anywhere.
Both came back "Evidence of Trimming" and received an A. Whats funny, anyone who has ever seen a stack of 55 Bowmans know they were cut horribly...no two cards are the same size anyways! I had no idea how they would grade with ink, didn't care and an A would have been fine...but trimming? No way...
