The Russian hallmarking system is not so complicated but you need to understand it and its varieties from year to year. It is a mission impossible to explain it in details here. Start with reading this link:
https://www.925-1000.com/Frussia.html In another link the same questions about books was asked. See here:
viewtopic.php?f=46&t=52744
As to the notches. No Aguest, not the "cut" corners, they are rather "correct". However, before 1882 there were no notches on the fineness mark, but as from 1882 it got notches. The corners are always cut. See pictures below and compare:
Note the years and look for the notches on the 84-mark on the mark to the right. Hint! Look up and down ;-))))
Also compare the right mark with the fineness mark on cww1960' s the egg holder. Look at the year! Actually there would be much more to tell about the fake mark, but I don't find it necessary to teach fakers. An good advice given on these sites many times is that "
Learn how a genuine mark looks like in all details then you know what is a fake mark" There is only "one" official and genuine mark but countless fake marks and they are all different.
Got it?