The 1974 car had about 225,000 miles on the mechanism and the shafts were indeed worn and wobbled, but they were complete.  I pulled the wipers from both cars and it seems that the 1975 had been taken apart and not correctly assembled.  The C clips holding the shafts were missing as were some of the washers.  They had cleaned it up a bit, but it was not right and this was a chance to fix it correctly for another 100,000 miles or more.

 

Overall Wiring setup.  Note that the dark-blue wire looks black and the stripe is hard to see.  I had used Goo-be-Gone and it removed the stripe, so be careful when you work on the wires:

 

 

Here is a comparison of the two:

The top part of the image is the 1975 with the extra tab welded on to hold the pollution control canister.

The lower part of the image shows the rubber isolator that bolts through the firewall.  That is bolted through behind your speedometer, to the right of it when looking forward and it is best to remove the steering wheel and speedometer to get to this with ease.  

Top left shows where missing washer should be and bottom left shows the missing washer.

 

The 1974 car had the circlips in place.  Notice the circlip just above the nut.  This is a C-Clip with flat (E-Clip-Like) edges, but it is not an e-clip.  I suppose an e-Clip center could be ground down to mimic this if you lose one (or two).  Lower arrow shows the washer that was missing on the 1975 car..

 

The clips and washers in stack order shown.  Easy to remove.  I put the arms in a box in case they went flying and I just used a small screwdriver to push the ends off of the shaft by about 1/3 per side (numbers 1 and 2) and then finally on the air-space (number 3) created by that to slide them off the last 1/3 into my hand.  Nothing flew because I used the box (Mr. Prepared) or was slow, or lucky or it was some sort of divine intervention (not sure?????):

 

 

The primary rubber gaskets removed and you can see the rubber isolator mount was still in one piece on these:

 

You can see the rust damage.  The internal bushings in the main threaded mounts are only at the two ends and thus the middle is not supported.  Lots of leaky seal time will fill these with water and rust-out the chrome.  I could have used another wiper assembly, but these will work fine greased-up and I doubt this car will see much rain or be stored outside.  My silver paint on the pivot arms is an improvement over the way they looked before:

 

Painted and cleaned-up and a new rubber isolator for the bulkhead: