Yeah, the local Saab dealer in Old Saybrook, Ct. imported a few W123 200's with carburetors back in the mid 80's. I know of one for sale in a lot with 150Kmiles plus on it. Mercedes did continue to make and sell them, in various markets without smog regulations where they felt the carburetor was a better cost vs. benefit trade compared to a fuel injections system. To get a registration and title in Connecticut you had to show the EPA and DOT releases, so I am sure they were obtained for those carbureted engines. But they are rare. Is your engine a 1.8 or 2.0 liter?
1986 Euro 190E 2.3-16 (291,000 miles),
1998 E300D TurboDiesel, 231,000 miles -purchased with 45,000,
1988 300E 5-speed 252,000 miles,
1983 240D 4-speed, purchased w/136,000, now with 222,000 miles.
2009 ML320CDI Bluetec, 89,000 miles
1971 220D (250,000 miles plus, sold to father-in-law),
1975 240D (245,000 miles - died of body rot),
1991 350SD (176,560 miles, weakest Benz I have owned),
1999 C230 Sport (45,400 miles),
1982 240D (321,000 miles, put to sleep)