Dane:
Working with the files in 17 will require a migration process to handle the new attribute Building Materials. I think the answer depends on the work to be done: if simple edits, then may be best to keep the projects in the older version, or just bring them into 16. If more substantial work is to be done that will take advantage of the new features of the current (17) version, then the time spent on migration would be worth while. It is a similar issue with current projects: is it worth the time to bring them forward into the current version, or best left in their original version.
You should add a Signature to your Profile (click the Profile button near the top of this page) with your ArchiCAD version and operating system (see mine for an example) for more accurate help in this forum.
David