The leather dont look too bad to be fair...A good clean and feed...Hopefully the stitching hasn't rotted...but still if it has then it can be re-stitched..I replaced some piping for someone recently...Its best not to use the old stitch holes though...
Looks like an outside temperature gauge. My Silver Shadow 11, from late 70s, has one very similar but a different make, which goes to +50 degrees, so similar ball park figures.