Latitude E6420 XFR Toughbook

Hello, here's the issue I'm having.  My current screen, which happens to be a touch screen, has gotten all purple and drippy to the point where only half of it is readable.  Now, there are plenty of these toughbooks that are in fantastic shape for sale on Ebay, but the uncertainty of whether or not the laptop I receive has a screen which is on the verge of also dying is leading me towards replacing the screen on my current XFR.  I would hate to spend $500 on a different XFR on Ebay only to have the same problem occur in a couple of months.  So I'm now looking for this same touch screen, which obviously isn't available on Dell, so I'm left to find it on Ebay as well.
What I have found is that no one has the touch screen version of it, only the non touch screen.  So I'm left to guess.  Are they swappable?  
What are my options??
Thanks for any help anyone can give me.
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