If DVAP can sell you a nice for 600USD including shipping it doesn't sound to bad. Its a 53 year old car...
Make sure the metal under the lower lip trim is solid. The trim has a sort of wide band and often covers this common rot area underneath. I have a very solid, straight 64 de Ville deck lid, but it is tentatively sold. Shoot me an email to email@example.com and I can put you on my Wait List. My price is usually about $150 for a good solid straight deck lid. Due to size, you would have to pick up or arrange transport.
Tim, I checked the Wait List and you are there. I start getting a blast of emails from everyone for parts Feb & March and hard to remember who has contacted me. As I like to say "I forget everything...but Excel remembers everything!"
Tim, It depends on the part. I have some items I only have 1 other person on the Wait List and might be a recent add. I have some very in demand items where I might have say 16 to 20 people on the Wait List spanning back 7 years. I checked the 64 deck lids and have 8 customers on the Wait List spanning back to Feb 2015. Here is the break down of adds: I have 5 customers added in 2015, then 2 in 2016, and you are the one I have added in 2017. Sometimes customers that have been on the list a while have already found the part or have sold the car, but I never take anyone off the list until I confirm or cannot get a response once I have something available. So, my best guess assuming I bring in 3 to 4 in the next 3 years, but factoring out a few people that already found or don't need a deck lid, would be about 2 years. I just put 2 bumper ends in the hands of customers that had been waiting 5 years! If you are ready to restore right now, that is probably not good news, but if you are doing the long gradual restore like I am with my 64 CDV 2 years is a drop in the bucket! All a matter of perspective! :-)
If you haven't found a trunk lid for your 64' I've got two lids in excellent condition, email me at firstname.lastname@example.org