The short answer to the original question is 'yes', the long answer is - well, it is very long with lots of 'ifs' and 'buts', issues, problems, 'dos' and 'don'ts' and varying experience and opinion.
Before drafting this response I searched again for 'numbering', 'numbers', 'auto' 'automatic' etc. and found many useful 'how to' threads and hints.
I concede that if you search for 'arn' you won't get much, if any at all - but why would you only search for 'arn' ?