as an apprentice motor trimmer, i would recomend you bite the bullet and take both cushions to get re trimmed immediatly.. even thought you cant see the freaked cushion cover, the foam wears fast once the other cover is off... and replicating the same shape costs a bit..
feel the back of the aftermarket seat covers you have, if its smooth and silky, you should be alright, but if its slightly ruff, except to pay for foam shaping in about a yaer, freak it gets annoying, you sit down and ur ass just hits the bottom of the frame lol