Re: Inside rail bumpers-2005 Proline 25 Sport CC
They are called 'coaming pads'. Being a 2005, they may still be available from the Proline factory. You can check their site or contact a local dealer.
If they're not available, they can easily be reupholstered (or duplicated if missing) by any local upholstery shop. I do them at my shop all the time. This way, you can have a customizing done to the if you want. I have custom embroidery put in them a lot, usually the boats logo or the name of the vessel. It's not expensive at all. You don't mention where you are so i can't help you as far as upholstery shops go.
http://www.prolineboats.com/