Você está perdendo o ".":
-t STAMP
use [[CC]YY]MMDDhhmm[.ss] instead of current time
rinzwind@discworld:~/test$ touch -t 200001311151.11 teste
rinzwind@discworld:~/test$ stat /home/rinzwind/test/teste
File: ‘/home/rinzwind/test/teste’
Size: 0 Blocks: 0 IO Block: 4096 regular empty file
Device: 815h/2069d Inode: 1308353 Links: 1
Access: (0664/-rw-rw-r--) Uid: ( 1000/rinzwind) Gid: ( 1000/rinzwind)
Access: 2000-01-31 11:51:11.000000000 +0100
Modify: 2000-01-31 11:51:11.000000000 +0100
Change: 2015-02-28 21:56:48.514848834 +0100
Birth: -