Possibly cleaned .
Remember that there were lots of issues surrounding the striking of Dollar Coins in the early 1950s.
You will find Silver Dollars Of 1950 through 1952 with both somewhat satiny surfaces and some with a very chromelike appearance due to the use of heavily polished Dies.
There are numerous examples of true Prooflike coins made for collectors and of circulation strikes that appear Prooflike but are just business strikes from fresh Dies.