I think following is very rare amazing cover. Look at it and you decide.
I think it's amazing, not because error made by postal service employee but look at the coincidence with error in year as you can see 1961 correctly if you reverese this cover as "9" & "6" also blend with each other or you can see "1" in 1961 is stamped incorrectly for both "1".!!
I think it is "1" which is stamped incorrectly.
Also I saw one more cover with similar CDS error without Gandhi stamp. (But lost in transit to India).