Yes. It was universally assumed the the War would be over in no time flat. As an illustration, the Union enlistment period was 90 days! Going to war had a festive, jingoistic feel about it.

There was no standarization in uniforms, so certain unit commanding officers picked garb more suitable to the parade ground than as battle wear.

French soldiers in Algeria were known as Zouaves and their brightly colored uniforms were adapted by numerous units. Thomas Francis Meagher's 69th New York Regiment (later called "The Fighting 69th") wore red uniforms better for hiding blood than the wearer. They had a tough time of it that day but fought bravely and left the field in an organized manner in contrast with the Union Army as a whole which was routed.

All the best,
Dan Milner