Yes - they were hoarded in bulk in the early years following the debasement of .925 silver to 50% in 1920. Many people, not just collectors, wanted the higher silver content. That's also why you see so much high grade silver from 1942-1946 after the removal of silver in 1947.
As for the 1920s issues, yes fewer people hoarded them as they were debased, but it's also partly due to the shallower portrait from 1920 which meant the larger silver wore much more quickly.