Quoted from Pinball-DOOD:
I know the wooden legs aren't original but my machine has red markings where the old legs were! I believe Gottlieb (like every other company) put any legs that were available that day on the machine during its production. These were money making machines and not for home collector. Most of these older pins show differences in terms of characteristics including artwork differences, parts used... so who knows!
The red flat legs were only used in 1956 on a few games.
From 1957 they went to 31 inch cream flat ( not ribbed ) and then around 1961 approx they went to the 31 inch ribbed.
PBR only sell the ribbed. The flat cream legs are very very hard to find. The flat red as used on games like Auto Race 1956 are even harder to find.
Operators would not have cared what legs went on the game when it was moved around so it might have had red legs on for 50 years but it wasn't Gottlieb's doing