I found this Q&A column in the magazine Traffic World (Dec 16th, 2002), which is a transportation shipping magazine.
Question: Our company is engaged primarily in international trade and we are considering a conversion to all metric in our sales and production processes. Can we provide shipment weights in our bills of lading for trucks, railcars, and ocean shipments in kilos? In our bills of lading, are we required to provide the domestic truck lines and railroads shipping weights in pounds? Answer: Since you aren't required to provide weight information at all, you can provide what you voluntarily choose to in any form you like. Presuming the carrier bases it's charges on weight, it's the carrier's responsibility to determine weight. This is most clearly spelled out in regulations developed by the Interstate Commerce Commission and now maintained by the Federal Motor Carrier Safety Admninistration concerning motor carrier bills of lading, in which motor carriers are required, per 49 U.S.C 14706(a), to issue bills of lading containing, "(weight, volume, or measurement of frieght)"; Code of Federal Regulations, 49 CFR 373.01(e). But the underlying requirement applies to all modes. Furhtermore, you may recall that back in 1975, legislation was enacted "to designate the metric system of measurement as the preferred system of weights and measures for United States trade and commerce"; P. I. 94-168. Nobody's paid a lot of attention to this, including the federal government (which was supposed to have completed the conversion within 10 years), but it's still on the books as 15 U.S.C 205a eq seq., and if you need support for using metric measures, this should suffice nicely. I just found that interesting, thought you guys would too. Brian