I recently bought an old Stanley S4 plane (that's the one with the steel body instead of cast-iron). In case it matters for the question to come, this is a later model with a raised ring on the bed to help stabilize the front knob and the lever cap has the kidney-shaped hole. This means it was produced about the same time as the Stanley Bailey type 16's. Between 1933 and 1942.
I'm not sure if the japanning on the bed is original, but it looks to be. The (apparently original) black japanning is only about 75% there mostly missing behind the rear knob (tote). Some prior owner painted over the missing 25% of the japanning with some ugly green-tan paint.
Now, I own old Stanley Bailey and Stanley Bed Rock planes close to the same vintage (and much older), and the japanning on the bed is different. The japanning on these planes is very thick and tar-like.
The remaining black japanning on the bed of the S4 looks like black enamel! It doesn't look like the tar-like japanning on the Baileys and Bed Rocks. Would someone familiar with the S4 verify this? If you own one or have seen original S4's or S5's, is the bed finished in black enamel?
This is just the bed I'm talking about. The frog is cast iron, and appears to have the same sort of japanning as the other Stanley planes (the tar-like stuff).
I'm not a collector, I'm a woodworker, and am using this plane. Still, I would like to re-japan the bed since some prior owner did such an ugly job, and I'd like to do it as close to the original as possible.