Is the pad to replace a worn or damaged pad? If so, do you have the original?
What is the model year?
Straight sections are easier to have made than curved sections. Having the original bolster's backing in good shape makes it easier and less expensive to fabricate.
There are premade straight bolsters available on the internet but the color won't match. If you are picky, custom made is the way to go. If the boat is not very old, you may be able to order through Grady. If older, it may be possible to find out who made it for Grady and order from that supplier.
A photo may help.