To check the paper and or grill mark? Were none of the 194's ever used. With only fifteen discovered, how could we be sure that none were used. The post mark date would be right. It is not the 1881 issue, that was issued on Aug. 7. It doesn't look like the 1875 issue, that was usually cut apart by scissors. I guess that was my question, how could you tell unless it was removed from the envelope.
It was used in a very small town in Maine, which is just the kind of location where a later usage of a 147 might occur. Population was only about 2200 at the time. And those do not appear to be soft paper perfs in any case.