I recently refurbished a Brooks B73 saddle. Several years ago, I repaired the carriage of a Books B66.
The B73 is distinguished by having three coil springs- with one coil at the nose of the saddle, instead of a plain bolt (B72 and B66) or a hairpin spring.
Last weekend I repaired the leather of a Brooks B73. This was not particularly difficult, though care was needed. I tensioned the saddle carefully using the tensioning nut. I let that "set" for several days, then applied a coat of Books Proofhide.
Today, I put the B73 on my Schwinn New World. The saddle "looks the part" and matches the bicycle's condition nicely. The leather is in good shape, but the saddle has enough honest wear to work well with this project.