The only true way to know the shutter activations if for canon to check it themselves with their service software.
Anything else really is guesswork. The file numbering system is a poor way to judge except by people who have owned the camera since new and take steps to keep the numbering consecutive.
I don't think it's worth going back and paying double when the shutter probably won't fail before you're ready to off it. How many shots do you average? Even if the shutter does fail down the road, it's replaceable for $160-200 i believe.
Just as a point I was messing around in the menus and clicked the manual number reset and the camera than went to the next folder number. On a 30D a folder is 10,000 images. So did I just mis-click in the menu, or add 10,000 actuations 
It's unfortunate that Canon hides this information.