I only collect one pre-war player and I have one major rule when it comes to his cardboard: I want it to be slabbed. I don't care what the grade is and I seek out lower-conditioned cards so as not to go broke but I do like knowing the cards I'm buying are real. I also enjoy knowing they're better protected considering they're harder to come by. Though I want them graded, I'll still buy 'em raw if the price is right and worry about the grading portion later.
That's exactly what I did when I came across the above W515-1 Strip Card from 1923 of Brooklyn Hall of Famer Zack Wheat, my lone pre-war PC guy.