Forum;
Referring to Item Nos on this exploded assembly diagram of lower A-Arm will help (source GCP.com site, for B20 Amazon).
...I recall lower damper mount (Item 36) on my '66 (so before B20s were fitted) has two securing bolts, and only one is shown here, but that is of course a different part from Item 13, which R122 is referring to...
Cheers