It is very interesting issue. I remember, once you said "оценивать русские монеты в час по чайной ложке" about NGC grading. Now, after russian grading one of these roubles by Shiryakov, you are asking for help?
It's a pun, wordplay. Musor means trash, insulting word for cops in Russia. The car is Maserati. So, police car Maserati means Musorati Or you can say Trasherati
5 Rouble 1904 in NGC slab MS67 is worth above $500. Well, let's say I know people who is ready to buy such coins (1903 and 1904) for that price in quantities.