Yes, salted SHA1/MD5 is generic, iterated sha1 is apparently Samsung-specific. Yes, it makes no sense to attack sha1 if you can attack md5. BTW you would be surprised how weak the pattern lock is, it doesn't even make sense to attack it on GPUs. Still, long passwords or PINs can be relatively secure (and even more secure on Samsung). Pattern lock is VERY easy to crack.
P.S as of Android Jellybean 4.2.2 (Nexus 7), the sha1/md5 scheme is still in use.
P.S as of Android Jellybean 4.2.2 (Nexus 7), the sha1/md5 scheme is still in use.