The so-called seals are a result of installing the poly bushings. The factory parts do not have any seal in the bushings asit is not necessary.

Actually there are seals used with the original bushings. I suspect that many of them have turned to dust or were not reinstalled after some suspension work, but there were seals in there originally. Bunch of discussion in this thread: http://www.classiczcars.com/topic/48661-spindle-pin-rubber-washers/

 

Here's a couple pics from that thread:

 

So the question remains.  Are the seals necessary and or desirable if you switch to poly bushings?  I don't have the parts yet so  I can't test fit it.  And I have never had my hands on the poly bushings to know how they would fit.  I haven't placed my OEM order yet, so I could leave 4 seals in the warehouse for someone else if they are not needed.

Because of the way the poly bushings work, they make the seals unnecessary. When you install poly bushings, they are designed to be crushed a little when the hardware is tightened and that bushing crush eliminates the gaps that exist with the stock style rubber bushings.

 

You don't want those rubber seals in there getting crushed along with the bushings.

Actually, one remaining question is "should you replace those bushings with PU bushings?"