This is not a question that can be answered yes or no. In some cases more recent surveys have shown Perring's published reports to be spot on, while in other instances he can be quite a bit off. I have found what appear to be errors in the computational handling of his field data for the Red Pyramid, and I suspect an error of a similar sort was made within his Khafre report. In other words, in a few instances I believe he may have measured more or less accurately but then made mistakes when later interpreting or transcribing his field notes.
I would suggest using his work only in context with other surveys.
Lee Cooper