I just replaced all the weather strips on my 67. It can be bit tricky, especially the ones on the inner side of the doors, as mentioned earlier. The are pushed into these holes in the door, which can take some strength to pull out. It helps to spray 'm with some lubricant oil, and with enough traction (and frustration), they will come out eventually. I taped the paint to prevent damaging it. Some is true for placing back the new ones: apply enough pressure. I just put my hand over it, and sarted hanging on it (with a closed door). Some of 'm take quite some strength to push in.
On a 67 you don't necessarily need to take out your doorpanels, since the upper part of the door is metal and impossible to take out. Only when you want to lower your window a bit further it is indicated. That is not always necessary.

There is one srew on the outer side of the door that need to be removed. on the new weatherstrips I bought from Classics, I had to drill this hole myself in order to replace the part.

Here are some of the pics I took when I did mine. The arrow shows the sight of the screw.