NSMutableArray arrayWithArray: vs. initWithArray:

Question

These both work in my app without any noticeable difference:

1)

theArray = [[NSMutableArray alloc] initWithArray:[NSKeyedUnarchiver unarchiveObjectWithData:theData]];

2)

theArray = [NSMutableArray arrayWithArray:[NSKeyedUnarchiver unarchiveObjectWithData:theData]];
[theArray retain];

However, are they really equivalent? (1) has an alloc statement, whereas (2) does not. Is one preferable over the other?