Historical question on Formatted Read

A quick historical question. I am working on an old Fortran 66 program in which the original programmer went to great lengths to provide detail precision on the read format statements for a fixed field input.  Here is a short example:

(f10.3,f10.4,/,(5(f10.5,f10.2))

Given the generic Fw.d descriptor, I have always assumed that during a Fortran read, the compiler only uses w and that d has no effect and in fact is ignored.  Was there a time when this was not true?   I did check to see if he might have shared this format with a WRITE statement.  He did not…it was only used for READ.

Thanks….