PER CURIAM:
The main objection is that one exhibit was admitted without sufficient foundation. But we hold there was some identification and that the objection to admission was not specific enough.
As to the necessity of preserving material footprints, the point is a good jury argument, but such procedure is not a legal requirement. United States v. Hull, 9 Cir., 441 F.2d 1165, decided May 10, 1971.