We have an International Land Yatch 1974 with the same valances as you.
We did not bother to replace the screw tabs (if I think I know what you are talking about - the ones wich prevent the curtains from running off the end of the tracks?). Being hidden, we just put either small "binders clips" or very small clamps- less than 2" long.
The front "room" is the only place we have those. No lighting behind them.
You'll be amazed at what is NOT in the book !!!!
We did not have a book for our 1971, so I think we dealt easier with problems. Not faulse info.
We just bought a 1990 Excella and the book has been nearly more useless than useful.
3 out of 4 of the drain valves are not where the book says (still looking for them), the switches, kitchen and bathroom are not as described, the electrical diagrams are not always acurate,....etc...
I think your Excella may have more in commun with our International than with our Excella. They where using - I suppose - same switches, valances,....... We may never know, as we cannot access some more central information