'78 300 series ID please (Also in Diesel Discussions)

[Benzitis]

I have a line on a '78 300 series cheap. Owner wants to get rid of it due to electrical and space concerns. I haven't seen it yet, but I'm pretty sure it's a 300SD, because it's a four-door sedan. I got the VIN from the title. Can anyone de-code it for me? VIN: 12313012066609

Thanks! Benzitis

[Gmazzini]

sounds eo me that its a w123 a 300D.