I think you are safe keeping that 7070.
I do not think Dansco has ever used PVC. As long as I have been using them, the pages and plastic slides have been completely safe for coins. My oldest Dansco albums are 27 years old now. My Dansco 7070 album is 18 years old. No problems, no complaints.
There have been albums with PVC problems; the Harco brand is a good example.
If your final page only has the Bicentennial coins, you can replace it. I had to replace mine to get holes for the Commemorative Dollar, ASE, Statehood Quarter, and Sacagawea dollar (my original page had Bicentennial and the SBA).
I bought mine from Wizard Coin Supply...
Dansco Replacement Page 6 - US Type (Modern US coinage)





















