Are the bake and broil elements in my Frigidaire oven interchangeable?
You do not list any product model so there is no way to provide a definitive answer.

All I can say is that the majority of bake heating elements are a single large loop around the bottom of the oven, while the broil element is usually densely looped back and forth with support struts holding the loops together.

There is likely no overheating safety hazard as the shorter length bake element is going to be of lower wattage than the longer broiler element.

The main concern I would have is if the bake element has any support hanging from the top vs setting in the bottom. It was not designed to hang from the top, so if it is unsupported except at the back, over time the metal may droop down into the oven cavity and create a contact burn hazard.

,

For cooking purposes, the lower wattage bake element will fail to be an effective broiler element because of the large empty area in the center of the single loop.

Broiler elements are used for browning and so you will get browning only in the area where the bake loop passes close, but everything else far from the loop will not brown. It will be an annoying experience requiring food to be constantly shifted to be near the bake loop.

Just buy the correct broiler element and do it right.