Yup...EPC confirmed... OEM part numbers are the same in the 300SD or 560SE, I also checked the 560SEC...all same except for in the 560SE, there is a footnote and chart, from what I can determine they have higher part numbers for the heavier applications (more equipment) and the spring bearing part number that goes in the 300SD looks like middle of the road in the 560SE....

so I guess I'm going to have to call H&R

300SD


560SE


Here's the footnote on the 560SE as a PDF
https://www.dropbox.com/s/2ch5v0mdempf8vs/w126%20560SE%20-%20Front%20Spring%20Chart.pdf