Brian,
I think they are slightly different, but I have one of each on the shelf I can measure and let you know.  FYI,  ScottyR mentioned he has used Yamaha KYB springs on the Sachs shock.  4.8 is really light, your buddy must be a little guy!  I'm 185 but any heavier and I'd have to go to the 5.4.
If no good trade deals turn up call Les, he may have something.