I have no idea about the line of code "$1 = 1" - I'm no expert here, I used an existing spec file from Schturman and made a few modifications that I thought were right (again, I don't fully understand what I'm doing).

Also, Schturman helped me with building ambience.rpm packages and if I recall, there was no need for adding lines of code you suggest;
%files
%defattr(644,root,root,-)
%{_datadir}/patchmanager/patches/sailfishos-remove-overlay-colour-camera-settings - and yet, every ambience I make installs and works as it should, based on the spec file given by Schturman. (I really do have a lot to learn, sadly, earning a living gets in the way of free time to learn this stuff!)

I have now just used my ambience spec file with changes to suit my patch. The patch is now installed but does not show in the Patchmanager app list. The files are installed to /usr/share/patchmanager/patches/ - but I don't know if my 'unified_diff.patch is written correctly! (Doh!, Noob alert!!)