installing splash shields

I'm hoping to be able to spray undercoating on my 68 this weekend since it looks like it's going to be the last good weekend before winter. I need to get the splash shields in place before I start masking off the body. I took this car apart in 2013 so I'm a little fizzy on some things. I seem to remember the splash shields were a pain to get off.

I just tried to slip one in place and it's binding up. Do I need to take the two lower fender bolds loose? It seems like this would help with the installation...or should they slide in place without doing that?