So, I dug out my 69 /70 manuals. It is the 69 three volume manual set dated Oct 68 and has updates up to 7/69. It does list 70 MY items that were due to come out in the next month (Aug/Sep 69).
The 69 manual has the following flag notes:
1. To the end of the 69MY
2. From MY 70
3. until Jun 69
4. From Jul 69
So, my 69 manual lists two versions of the steel lid:
901.512.010.23 with flag note 1 (end of 69MY) shown across all models (assumed to be the three bar lid)
911.512.010.10 with flag note 2 (MY 70) but, not on the S. This is for sure the five bar steel lid as the same part number is used in my 71 manual for the steel lid listed for the T/E.
The 69 manual also lists the aluminum lid:
911.512.010.00 with flag note 2 (from MY 70) for the E/S. This is for sure the five bar alum lid as the same part number is used in my 71 manual for the alum lid listed for the E/S.
Same methodology is followed for the steel versus aluminum valance part numbers using the same flag notes.
No mention of the aluminum bits used on the 69 for any models. Only 70 MY.
Further to the two different steel lids in the 69 manual, there are two different grills listed as well:
901.559.041.23 with flag note 1 (end of 69MY) shown across all models (assumed to be the three bar grill)
901.559.041.00 with flag note 2 (MY 70) across all models. This is for sure the five bar grill as the same part number is used in my 71 manual.
My 71 manual lists the steel lid for the T/E and alum lid for the S. The valance is a different story. It lists the steel for the T only and the alum for the E/S.