This is an important issue: How to recover these deleted archives to the best possible level? Time is running against the justice. 参与过64镇压的解放军将士全部去除档案中相关的记载.
US has a National Archive collection. There is no way the current chinese governoment will archive files related to 64.
A possible way is grass root try to organize (donote money and time, form a trust) to collect files, validate them, and archive as records.