Fixed the 500c/m; apparently a "sync" issue. Got the gist of the problem, but am hard pressed to determine exactly what I did during cleaning/prep that caused the issue...

The F5, for its part, apparently suffered only cosmetic damage (a nice crease along the left front of the body and a battery holder that - glued together - does not align as snugly as it once did). No damage to the lens mount and the electronics all check out. Meanwhile, Nikon in Toronto has yet to render their verdict on the 28-70ED...