I am assuming that your webshots are of the cab in question. If so, you have a great advantage with it on a stand on it's end. It is more difficult to replace these items with the cab in place.

You should make references somehow to show the exact locations of key features as you replace parts. Also you will probably find the new floor boards have the holes incorrectly located. One feature that I learned about late in the process was the support bushings for the mounting bolts that go between the floor and the cab supports.

1951 GMC 1 Ton Flatbed -- It is finally on the road and what a great time I have driving it!
1951 1 Ton Completed

My Chevy Master 4 Door is on the Road!