IMO this would be basicly trying to swindle Tower for a minor problem of neglect. If you want to complain to anyone, call OS. just because nobody at your field checks their equipment for loose hardware, at least to your knowledge, doesn't make the mfg responsible. To expect a new plane because you lost @$2 in screws is part of what drives our costs up. Do you think warrantys are free? All this is figured into the basic cost of a product. Do you think the warranty on your car is free? Far from it my friend. Dorsil needs to suck it up, buy some screws and stick on a little tape and go fly. Sheeesh!
The LA engines are infamous for loose backing plate screws, do you want to blame Tower for that too? If you read through the various beginner threads you will find a lot of places where people are advised to go back and recheck ALL hardware (includes engine) for tightness after the first flights and again on a regular preventative basis