D25 was introduced in '68 as all-hog flatback.
Sometime in '72 the archback was phased in, more than likely both types were made in that year before the transition was complete, and more than likely some all-hog flatbacks were still left over and being shipped out as well.
Guitars ID'd as '73 hog-topped archbacks by far outnumber any other year reported here and in internet listings over the years, so it seems that was the high point production year for all-hog archback.
In '74 a spruce top was phased in on the archbacked D25, but all-hog versions continued to appear at least until '75 and we even have a member who reports owning a '76, the most extreme outlier I know.
We periodically see guitars from '75 and later misidentified as 'hog-topped archbacks because Guild applied a Mahogany colored stain to the spruce tops for a while and called 'em "D25M"
Things are further confused by the fact that some of the all-hog archbacks got labeled as" D25M", too.
You're welcome and at least now you're a properly educated hater.
:glee: