[SS Tim]

Ok there were lots of mirrors both factory RPO and GM accessory. Plus aftermarket mirrors from many sources in many styles. This thread has diverted so far from the '68 baseline question that the answers become mirky and incomplete. My chart was for '68 and pretty much '67. The later trucks began using tripod (three point mirrors and the SPIDs called the WCjs for a while until "Below Eye Line" became the usual verbage. In addition to the tripods, Camper (four point) mirrors were introduced and the WCjr style went away with only the SRs being the HD truck mirror.
The camper mirrors are easy to distinguish with the four mounting points (or a common top mount) and heads that will swing inside or outside the verticle rotation point. This gives the daily "not too wide" and the all out camper "see anything" modes.

Mark the camper mirrors on the #3 truck are correct RPO DF2 and are the most common of the camper mirrors in a minimum width position.

We could all probably post up a bunch more pictures with "I've got this or that". But I don't see this getting a lot clearer. The problem seems to be people keying in on "mirror" without realizing the year to year variations which was not the root of this thread.