Hi Trev,
Bend the tabs back with a small flat screwdriver, it's pot luck but if you break a tab just get it tig welded back on or make a blob of weld over it.
Restoring old parts is something of a gamble, I know as I have 1920's nortons
In the last picture... is that ball and plate both steel, if so you can have it chromed as one without removing the ball and it will look and work fine.
Just a quick note about the rear engine bay panels, remember that you will need to drill holes in them for things such as alternator, starter motor cables , gear linkages etc.
Nice clean build