India Republic KM# 360 Rs. 5 (Khadi and village industries) coin has two variants for Mumbai mint (different mint marks, "diamond" and "M").
"M" mint mark is normally found in Proof coins. But, in this type of coin "M" mark has been found in normal circulation coin too. Another such example of "M" mint mark in circulation coins is KM# 405.
In ngccoin.com website the both the coins are listed: KM# 360.1 for "diamond" mint mark and KM# 360.2 for "M" mint mark. However, they do not have images in their website and wrongly mentioned in their description as "N" mint mark instead of "M".
KM# 360 is a scarce coin and this variant is very rare. Even rarer than the the two error coins found in this variant.
Please see the images below for reference. The source of the images is my personal collection. I request for this variant to be added in the catalog.

Thanks.