My daily riders Brooks is probably in worse shape than that (minus the mold). It has a missing rivet in the rear and the rear rail is outa whack. It's got a pretty good tear starting on one of the front rivets. Still going strong! I call it the butta 'cause it's like butta on yer.....well you get the point. When I got it it looked terrible and had been in a locker at a LBS for ever. I treated it several times on the top and bottom, slapped it on there and have been riding it for nearly 3 years now. I think this is the last season for the bugger though.........It's replacement is waiting patiently (NOS B5N) which I am sure won't be like butta for awhile at least.
Ya, so clean it and treat it! It'll be fine for awhile.