The seatbelt latigo is fine structurally, I just meant to point it out as not likely to have been original.
OTOH, if the rear jockeys came laced like that originally, the saddlemaker needed to be fired. When the saddle was made it would have likely been laced, but the skirts would have been laced to each other and then SEPARATELY the jockeys laved to each other and laid on top. Lacing through both jockeys and skirts together looks terrible, and prevents the skirts from flexing as readily.
The skirts were probably relined, and rather since that requires removing the lacing it was easier to do this than pulling the skirts off completely and doing the job properly.
Likewise, I almost guarantee the seat was replaced because of the hash job of stitching. In this photo:
http://www.auctiva.com/hostedimages/showimage.aspx?gid=5532&image=829970022&images=829970022,829972140,829970309,829970134,829972175,829970076,829972239,829972290,829972329,829970182,829970441,829970343,829970389,829970225,829972096,829972364,829972487,829972515,829970271,829972447,829972402,829972542,829970498,829970547&formats=0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0&format=0
…notice how the back line of stitching is done with a diagonal saddle stitch, where the front line is done badly with a skipping stitch. Even the hole are punched wrong, since the diamond awl was held with the long angle parallel to the cantle binding rather than angled at 45 degrees, which would have resulted in the same stitch you see everywhere else on the saddle.
What likely happen was the job was rushed as well, like the skirts. The original seat leather would have extended up and under the cantle binding, and replacing it would have required pulling the binding and restitching it.
Rather than do that, the binding was peeled back, the seat cut off, and a new (not even straight) stitch line grafted on to put the seat back in place. Believe me, sewing a cantle binding is tough enough work once, so adding a double stitch line makes little sense.
Not structural, but sure not very pleasing to the eye.