I was looking closely at my 1969 Super Reverb and noticed the tilt-back legs have "patent pending" stamped near the bottom. They almost look like new, no corrosion or rust, but that's the case with the rest of the metal parts on the amp also. It came with an original heavy Fender cover, so I suspect the prior owner never gigged with it and kept it covered when not in use.
I have seen replacement "vintage style" legs for sale from various sites, but not "patent pending" ones. I suspect they may be original, but would like to know when they first started being used by Fender to determine if the "patent pending" ones would have still been on amps built in 1969. By the way, since the Super Reverb is so tall, the legs measure 19 inches, compared to 16 inches on my Super Twin Reverb.