I had the chance to take delivery of a new 757 in Renton a few decades back , It had h only a few seats fitted , the rest was empty and I was surprised to find all kind of small junk left over on the cabin , with nothing better to do at 40.000 ft for 10 hours we filled 2 duty-free size plastic bags.. Debris included , rivets heads, gaskets, cables , insulation bits ..etc.. Strange that for 100 M$ no-one had bothered to make a visual tour and clean the aircraft before delivery.. On mechanic on board said that it was current to take a week " finishing" the aircraft before installing the interior. OK this was over 30 years ago .
Looks like old habits die hard..