FedEx drops boxes as well. I am leery of buying an amp without original boxes but no way would I pack an amp the way you have described.
Yes, FedEx or UPS, it doesn't matter. Heavier the item the the rougher it will be handled. A few yeas back, I had a 140 lb Jeff Rowland No 5 delivered in the original wood shipping case with all the original packing, I actually met the driver at the street. In order for the driver to get the package to the rear door of the truck, he flipped the create a few times letting it drop each time like he was handling a load of used auto parts. I helped him lift it crate off the truck on once it was on the street, I told him I would take it from there.
Once it was inside the house and the opened the crate, the amps look perfect, however, once I removed the top of the amp for an internal inspection, and both R + L channel plug-in modules were knocked out of their respective sockets and each had a number of pins bent. Luckily, I could straighten the pins without breaking any of them and the amp worked perfectly.
The bottom line is FedEx Ground and UPS tend to handle heavy packages very roughly. Both of these companies ship many 70+ pound packages of kitty litter, dog food, and other heavy bulk items from Chewy and Amazon every day and your heavy amps will get treated just like these packages.