I ended up buying the expensive one from BDR because they are close to me, and I could get it quickly. But I also did some investigation and found that a BECK/ARNLEY 0726331 from a MERCEDES-BENZ 1978 300D 3.0L L5 DIESEL appears to be the cross-reference match to the new one. I bought one and shelved it just in case: Here's the rock auto link:
https://www.rockauto.com/en/catalog/...+cylinder,1836
To be clear, I have not tried it yet, but it looks the part compared to the the BDR unit.
For reference, I 'll try to attached pics of the BDR unit I took when i received it.