Yes Golems work on any valid inventory. Iron Chests mod chests are a valid inventory, as are barrels, as are CoGs machines, as are Gregtech machines and so on as long as the block is set to appear as an inventory Golems will look at it, so as above the question is did you mark the source chest with a marker block (for a chest it doesn't matter which side you put it on some other inventories require the marker block placed on the side you access that section of the inventory from) for Clay Golems all source inventories must have marker blocks.
I have Clay Golems filling my RP2 Project Tables, some of the resources for this come from my Gold Chests (some of which were Iron Chests when the Golems were placed they still work even after the upgrade).