I don't think I'd bother with the metal - a 110/115 weighs around 320, a 130 won't weigh all that much more. Maybe it was a larger head but shouldn't weigh too much more. Look it up on NADA.
Your transom should be fine. Putting metal across the transom is usually an "Alert" that something is wrong with the transom to anyone that knows about boats.
That 130 should push that boat along quite well I'd bet - 45 ish or better. My 115 will just hit 40.