It looks like if you trim off the selvage you won't have enough of a seam allowance to match up the print. In this case I would leave on the seam allowance and match the print. Generally, you remove the seam allowance because it is of a denser, thicker weave that shrinks at a different rate when washed. You might have to iron that seam a little when it comes out of the wash but I could live with that. I say go for it.