Your 401(k) cannot buy gold bars.
Almost none of them can. The plan menu has funds, maybe a target date series, maybe company stock. No vault, no bars, no depository.
So the answer to the question is yes, but not directly. The gold happens after the money leaves.
That gap between the two accounts is where a surprising amount of damage occurs, because it is the moment you are most exposed to two different mistakes.
One of them costs you a percentage. The other can cost you twenty percent of the entire balance in a single afternoon.
Here is the whole sequence, in order, with the traps marked.