REALLY stuck on fork seals.

I may be interested in those, if you are trying to get rid of them. Just let me know what you're wanting for them.  
I will first need to see about this other thing I have going on.
I am in the process of possibly purchasing two kz650s, won a complete bike that runs albeit rough, the other everything but the motor.  I believe they are a 77 and a 78.  
Both titled and everything which is great because my frame is not titled and I was going to have to go through the antique title method in my state or the Vermont loophole.  
Both of the bikes were garage door and from the pictures the forks look in great condition so I may not need to purchase tubes anymore

But just in case let me know what you would want for them. 

Also, so as long as the total length is the same would it be okay if something else was different?  So for example if the total length is the same on the Z1 and mine, I should be able to interchange them, so long as other things match up like the calipers and the rotors etc, right?   I will go ahead and do a search on some of these things but figured there's no harm in asking
I know some people go completely custom on their front ends and do all kinds of crazy stuff but I'm not quite there yet. All I really want to do is get this thing so it's roadworthy, as cheaply as possible, so that I can get a antique title for it and start customizing it.  

epiphalactic post=861893So if I were to just get the forks from a dual model, will those just bolt right up? Obviously I would have obviously have to get the other disc, correct? But if I wanted to convert over to the dual disc model, it would just be essentially bolting it on? 
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Yes, the dual-disk will bolt on.  But you need to get all of the pieces.  The rotors/disks are different.  The forks are different.  The master cylinder is different. 
The single-disk is a larger diameter and thicker. The dual-disks are smaller diameter and thinner, to reduce weight.
Since the dual-disks are smaller diameter, the caliper mounts on the fork-lowers are moved down closer to the axle.  So the forks-lowers and disks need to be used as a matching set.
The calipers are the same, but you would need to find a right hand caliper with the correct piston size.
This style brake caliper came with two different piston diameters.  38mm and 42mm.  They look the same.
The dual-disk master cylinder has a larger bore.  Using the larger master cylinder may not be strictly necessary, but they are different between the two versions.
The spoke wheel on the "B model is drilled for the right hand disk.  It will bolt right on.  You just need to remove the chrome trim cover.