This line denotes the silicon information.
354A2C
The last letter is the part revision.
This is similar for some other parts in the atmega and attiny range (Not necessarily all). They have 6 characters - 3 number, 1 letter, 1 number, 1 letter, where the last letter is the revision.
Just for interests sake, on the top the four numbers:
1127
Are the year and week (YYWW). So your device was manufactured between July 4, 2011 and July 10, 2011