I received this in a box of race parts that came with a 1970 911S which I recently purchased. It was alongside a genuine 2.8 RSR 10,000 RPM tachometer (part number 911 641 304 00, confirmed to be a genuine 2.8 RSR part elsewhere on Pelican). According to a previous owner, the gauges were bought at a dealer in the UK in late 1973, but I have no documentation to back that up. The dates stamped into the housing reads 8/73 (see pics) and the ink stamp reads 9/73, so these are definitely of that vintage.
More pics here:
http://pg.photos.yahoo.com/ph/porschenut74/album?.dir=/75afscd
I believe that this is a very rare 180mph speedometer for a UK spec 1973 911 Carrera RS or RSR. It has the warning light for the parking lamps at the top of the gauge which indicates a genuine RS speedometer. See this thread on the 911S board:
http://www.early911sregistry.org/forum/showthread.php?t=10215
The km/h Carrera RS speedometer part number is confirmed to be 911 641 506 00, but this mp/h one has part number 911 641 506 29. Can anyone tell me if this is a genuine RS or RSR Speedometer? If it is, I imagine it's very rare, as only the UK uses MPH and had Carrera RSs delivered. I don't even know if you could get an RSR in the UK, and if it would have a speedo.
Thanks for your help. Just so you know, this speedometer and the genuine 2.8 RSR 10,000 RPM Tachometer will be going on eBay. Because I'm having to ask for the kindness of you experts, the proceeds from the auctions will be donated to a medicine fund for those who can't afford it at a remote jungle clinic in Palawan, Phillipines where a good friend of mine is a nurse.