IBM 83-key questions (repair and color)

My best-condition 83-key keyboard suddenly developed a bum spacebar, right in the middle of writing some documentation. Before I unscrew the two screws on back to open it up and take a look, can anyone tell me if this is a common condition and if it's relatively easy to fix? I've *never* had a buckling-spring keyboard develop a bad key (maybe I haven't had enough frustrating debugging sessions yet ;-) so I'm at a slight loss as to how to start repairing it. Was there a tech ref for the keyboard at one point, perhaps? Slightly OT, here's an 83-key that is *gray* (several pictures): http://www.clickykeyboards.com/index.cfm/fa/items.main/parentcat/11066/subc… I've never seen a gray variant -- was it official? If so, what system was it intended for use with? I've seen "skinny" IBM keyboards that were intended for use with the PS/2 model 25, but I've never seen a gray 83-key before...