Guild phased out the wooden foot switches at the start of the Thunder amp series (circa 1965). Prior to that they were hard wood with a fixed cord and full rubber anti skid bottom. I have seen three styles: Two stomp switches for Reverb + Tremelo (98RT AMP) with fixed point wiring to the amp, a plugin Single Stomp switch + cord w/phono plug, assumed for Tremelo but not marked (66J, 99J, 100J, 200S) and a mini "doorstop size" Single Stomp switch, assumed for Tremelo but not marked (20RT, 40T, 50J) where the 20RT was hard wired to the Reverb/Tremelo converter amp and the switch only activated the Reverb-tremelo was a rocker switch. The dual stomp switch pedal of the 98RT was around a 5 inch square with a rise of about 2 inches. The single stomp switch was around 6 in x 3 in and a 2 inch rise. The mini switch was around 2 in x 4 inch x 1 in rise (all my numbers are estimates. I never measured these pedels and have long since sold the amps with pedals they came with).
Thunder 1RVT, Thunderbird(s), Thunderstar, Superstar and Maverick used the cast aluiminum pedal as shown by hideglue. The Thunder 1 RVT and 1st style Thunderbird and Superbird amps had the pedal hardwired, others have RCA connectors. The Superbird series of amplifiers used the cast metal pedal and added a 3rd unmarked middle stomp switch for the built in Fuzz Tone.
The Thunder 1 (no Reverb but with Tremelo) did not use a footswitch. Instead the Tremelo was activated from a front panel switch. The only amp I am unsure of is the very rare Super Thunderbird- I assume a footswitch was used but don't know if it was hardwired or plugged.
One other item...Guild made an unusual tone modification pickup that had some active equalization features. It divided the frequencies into 3 bands. The cast aluminum foot pedal was used in the accessory with a 3rd stomp switch added like the Superbird footswitch. Check out Guild-of-Grots site. I think he has one of those gizmos.
I am not sure what wood was used for these pedals but it could have been mahogany.
Also, about ever 2 to 3 years one of these wooden pedals pops up on ebay. In the begining they sold for a reasonable $20-$30 price but the last one(s) I saw were sold around $80.
M