That could depend on rolls. I am also at this moment reading a
book on armor written after WWI by a Harvard professor, Bashford Dean, who seemed to be of the opinion that metal armor was worth more against modern weapons than people give it credit for. This even includes references such as a recovered civil war (American civil war! Who knew?) metal breastplate which stopped .45 pistol rounds when tested, and one (but not two) Mauser rifle rounds, and metal armor demonstrated against machine guns. He even likes the idea of aluminum armor, although that might be optimism given by the rarity of the material, it had not been tested much then. This is of course at odds with most other sources I've heard (metal armor is worthless against modern rifle rounds). Ned Kelley's armor comes up a lot, I've heard the opinion that it's unlikely it could have stopped rounds with smokeless powder behind them though. There were also a lot of real attempts by the United States ordnance department in late WWI to make armor effective against machine guns or service rifles, and they didn't find any of numerous designs satisfactory. Then there's Brewster's armor, which stopped a Lewis machine gun reliably. It weighed 40 pounds and was very cumbersome though, I don't
think it was ever used in battle.
Anyway, I would say it's entirely possible it could be effective. While looking around I found some weird examples of armor actually made in the first world war, at least on an experimental basis. I might have to bust out the calculator before deciding how much it weighs though...