I recently posted about my FG-140. I rep[laced the stock saddle with Buffalo bone. Purchased at the link below. Nut and saddle $3.25 free shipping. They need to have the same fitting as any new saddle or nut would need.
As you can see in the attached photo the saddle is slightly narrower than was the original. If you wanted to fix that, for cosmetic purposes, I'm sure you could fill in the gaps with, a small piece of rosewood shaped to fit, then glued in place with with yellow glue. I don't think it makes that much of a cosmetic difference to merit the extra work however. They fit the groove width perfectly, and are about 1/8" short on each end. I don't have close up photo, I'll take one and post it later.
Here is the link to the parts.
http://tinyurl.com/ogdomk3
Dan
