Hi Jesse,
Yes the Guild Thunder 1 RVT comes with a HARD-WIRED footswitch that is stored inside the back of the amp. It is held in place by a pocket made from heavy duty "cardboard" and a spring loaded clip. The picture you posted indeed shows the footswitch in it's storage compartment.
I suspect the guy you bought it from didn't realize the switch was mounted in the back of the amp.
The amp in the picture is a '65 or '66 model. It was the first amp I owned back in the '60 and I came to realize just how unique the Thunder1 RVT amps sounds after I got rid of it and moved up to a bigger amp. The Thunder 1 RVT has "speaker driven reverb" which means the output going to the 12 inch speaker is taped, attenuated and goes through a High Pass Filter to reduce the low frequencies. It is then fed back into the input of a 2nd lower power amp in the reverb circuit and then comes out of a 8 inch speaker.
The resulting effect is a lush reverb with pseudo stereo effect. You will enjoy this amp the most if played when sitting in front and facing the amp. The pseudo stereo effect will become obvious and you can adjust setting of Reverb and Tremolo. This amp can yield a variety of vintage sounds by selecting the Bright, Normal and MIC input. The MIC input will drive the amp to be a bit more distorted. I usually alternate between MIC and BRIGHT. The amp also has a "bright" pull switch on the Volume knob that will definitely brighten up an already bright sounding amp.
These are great amps. Try different speakers to adjust the tone. I am presently using a JBL K120 in my black Thunder 1 RVT and the stock speaker in the later beige colored model. The JBL is overkill for a Thunder 1 and makes it a heavy amp but I like the combination.
Have fun!
M