[CR]Unusual Suntour Chainstay Cablestop

Here's something I haven't seen before :

http://ebay.com/<blah>

Is the arch (perpendicular to the chainstays) on the front side (where the cable slips through) a device for countering chain-suck ??

I would like to buy a regular chainstay cable stop, hopefully one that says "Suntour" on it, for a 1977 bicycle. Exc or NOS condition please. Anyone on this list have one for sale? Thanx,

- Don Gillies
San Diego, CA, USA