Yes for me. Of course I don't know every single character by heart but with a little bit practice and the help of a dictionary you can read a lot. You can even download some seal script fonts and make all the Chinese websites shown in seal script.
With some training, people can read seal script inscriptions because the structure is already fairly close to regular script which is what people use today.
The radicals are written in slightly different styles from today. It actually makes sense. Seal script is a very artistic form of calligraphy, so people use it for their seals hence the name.
An example of the "drum" character:
http://www.guoxuedashi.com/zixing/yanbian/11208mb/
The horizontal arrow is the time line, starting from oracle bone script. The 4th one of the first row is seal script and the last regular script.
The idea depicted here is hitting a decorated drum on a rack with a drum stick holding in the hand.
If you look at the picture on the upper right, you can make out "tian xia" and "wang" -- all under heaven (i.e. the world) and king (the character for emperor isn't invented yet)
Good catch. But that just adds more to my point: modern Chinese can understand seal script to a large extend because seal script is the ancestor of the modern (non-simplified) Chinese. My guess is that neither you nor I are "Indiana Jones".