Stopped by the stealership and priced out new door weather strips. With a straight face, he told me it was $600! I gave him a couple of seconds for to smile, and give me the real price. When it was clear he was serious, I thanked him, picked up my teeth, and left. 

Any advice on where to purchase replacement?

Try here...

http://www.lmctruck.com/

I second LMC. My dash came from them and couple of smaller items and they have all been good products.