I mentioned this in passing on the earlier discussion on 1158s Jeff: http://www.chronocentric.com/forums/heuer/index.cgi?page=1;md=read;id=44813

Not something I've seen on an 1158 before and, with Bonhams dating it to 1974, it's also an anachronism if that date is corroborated. Possibly added later if the owner liked the look of the scales on the Jarama but I'd need more convincing that it left the factory with that in place in 1974.