A wind turbine blade has an upper shell member and a lower shell member bonded at a leading and trailing edge of the blade with a bond paste applied between respective forward and rearward edges of the shell members. At least one of the shell members includes a first inspection window defined therein along one of the leading edge or trailing edge at a location corresponding at least to a design minimum bond width of the bond paste applied at the respective leading edge or trailing edge. The inspection window provides a visible access through the shell member such that a visible indication is generated through the inspection window when bond paste is injected and reaches the minimum bond width location in the chord-wise direction.