Those springs are replaceable. I don't have one here in front of me, but take a look at yours. I'm pretty sure both ends of the spring are held on with a nut and bolt. So changing the spring is a fairly simple matter of undoing the nuts, putting in new springs, and replacing the nuts. Tightly.

New springs are available; look at Wallingford Bikes website, here. They have both black and chrome. I would replace both springs, so you know they're evenly matched.

Alternately, if you want old springs (which have a reputation for being softer and springier and more comfortable) send me a PM in the next couple days; I am pretty sure I can get you a pair of springs off a ruined B66. Whether they'll be black or chromed I cannot guess, but I'll know when I look.