Thanks for that. I have the first parts book that Draganfly uses. I missed the 19-0738 part number. Unfortunately, it's "Out of Stock" at Draganfly.
I think you will find the Lucas
MCH66 headlamp reflectors or equivalents are in stock elsewhere, and probably nearer to home, however,...
The second one, with an 00-5145, I see only "European" and "France" types, nothing for the Firebird, unless I'm missing it again.
...19-0738 like many other motorcycle reflector units of the time (including 7") were vertical dip*
suitable for riding/driving on the left or right-hand side of the road, however, replacement reflector assemblies available now can also be left or right-hand dip, especially if they are not original BPF.
* Up to T160 and '76-77 T140 etc.
T160 parts book:
France had yellow headlamps and those reflector units with 411, p45t bulb I believe, dipped to the right...https://andover-norton.co.uk/en/shop-details/17436