§ 92. Erroneous bills of lading or receipts, issued in good faith, excepted. No person can be convicted of an offense under the last two sections, for the reason that the contents of any barrel, box, case, cask or other vessel or package mentioned in the bill of lading, receipt or other voucher did not correspond with the description given in such instrument of merchandise received, if such description corresponds substantially with the marks, labels or brands upon the outside of such vessel or package, unless it appears that the defendant knew that such marks, labels or brands were untrue.