Yeah, the Sandcrawler power droid colors are hard to judge because the only ref pics are in high contrast lighting that varies a great deal.
This to me is a bit of a Han Hoth brown coat/blue coat situation - do you want the color you saw in the movie, or the color the item was in reality on-set?
In reality, I think this is what the sandcrawler PD really was, which is the color of lightly rusted older industrial/construction equipment (for example a well-used backhoe/digger's bucket or the tray of a well-used dump truck) along with some subtle oil stains and very little metallic sheen:
(A) ACTUAL COLOR OF THE PROP:
If you look at the pic below, you can see the contrast between the rusty/red-brownish color of the PD's body versus the grey of the floor, the silver of R2D2 to the left in foreground, and the dull silver of the legs/feet. This proves that the rusty color is not just a product of the lighting/color balance in this particular shot.
This pic of the Hasbro variations actually (unintentionally...) summarizes all three shades that the sandcrawler gonk appears to be in various ref pic shots (though the one of the left skews too gunmetal and the tannish one on the right should be a shade darker):
However.... for most people, they think of the "gom-gom" shot, which looks like the pic on the left below. On the right I have included a look at the "tortured" PD from Jabba's Palace dungeon in ROTJ, because I think the lower part of it informs how the gonk color should look if you're wanting to match that "gom gom" shot look, which is a dull greyish metal (with a slight metallic sheen) with light weathering/grime/ corrosion.
This look is similar to what Hot Toys went with for their Power droid, though their weathering app is somewhat weak (a light "oil staining" look) but their base color is probably right for the "gom-gom" shot look.
(B) HOW PROP APPEARS ONSCREEN IN "ICONIC" SHOTS:
The feet and legs on Sandcrawler power droid are both a dull silver, with the (duct work) legs being a more reflective metallic sheen but also having a slight grease-like weathering which mostly makes them appear duller/darker than the feet.
Keep in mind there are a few small colored squares/"buttons" on the feet (one is red) so I'll have to post a pic of that.