Provided that the document bearing such a stamp does not bear a signature for the acceptance of a change to be written at a later date. 5. The collector may call a motorcycle or such a reference to the original apparatus to determine whether it is correctly stamped and whether the instrument so manufactured is considered to have been manufactured or is available in the performance of its duties, and if the original instrument is not manufactured within the time limit set by the collector, he may request payment of the tax or amount in due form; which is necessary to compensate them at the same time as the penalty provided for in section 44. Provided that, if the person is a licensed stamp seller, the collector may refund the amount actually paid by the seller, without the above-mentioned deduction, if he deems it appropriate. . . .