On pre 1850 gravestones, a script 7 is often mis-transcribed as a one. The reason for this is because the script 7 often has a really short horizontal line. You can determine that it is a script 7 instead of a script 1 (one) by: (1) the horizontal line is very thick, and (2) the vertical line is very thick. Both of these lines start out at the upper right of the 7, but then quickly thicken as they move away from this point.