You're welcome. I went out and took another look and the outboard end of the lower mount is pointing slightly forward so as to align the shock toward the upper mount also, so there's a left and a right shock mount.
I just checked the 47-54 FAM and it shows the 3100 lower shock mounts pointing down like yours, but that may be because it's really a '54 figure, with the lower rear frame hump. It would be interesting if someone with a '54 would let us know which way their rear shock mounts are installed.
The '48-'51 shop manual has no pictures of the shock mounting.
Last edited by klhansen; 05/27/2020 12:44 AM.