Steve
Bosun Supplies number is (888) 433-3484. Talk to Chris, she helped me a bunch. Mention my name and she'll probably remember, because I had to send back two rails (they goofed on the bolt spacing). It was definately a custom fabrication. You need to measure your holes PRECISELY. Mine were 13 15/16" apart at centerline. The bolt length from the base of the handrail to the end of the threads was three inches, with 3/4" of thread. Because they used a larger diameter than 3/16 bolt, I had to enlarge the holes in the deck and in the belowdeck rails. Once I got the rails and made sure they were the right dimensions, they fit right into the old holes on the deck with only a minor amount of grunting and swearing.
The new rails are sturdy as the dickens and look fabulous, and no more varnishing! Good luck!