Graeme, great work on cleaning up the front end components. I noticed that you replaced the end link hardware with NOS parts and this may not matter, however the end link bolt with the
WB (Wales-Beech) head marking used on 69's was a Grade 3 bolt with fine threads. For some larger GM vehicle applications the bolt used was instead a Grade 5, with 3 radial head markings as shown on your replacements, which is also course threaded. The correct bolt has no radial markings.
Original End Link WB Bolt from Skip L's 22K mile 69Z Survivor
My original WB bolt (restored)