Do you feel you can rate the experience level of the author by how the code looks, both in Perl and programming in general?
For some reason this question comes up from time to time, as if there is some fascination with it, but the answer is still "No". Experience and writing maintainable code don't always overlap.
I've seen lots of code, some from some very smart people, that looks hideous but runs well. In general it continues to run well as long as they are the ones to maintain it (or they hire someone very smart). Is this good? No, especially not in the long run, but it doesn't say a thing about their experience level. One guy I know does the work of several programmers, with few bugs in his code, but he writes very "old school" C that would make most people cringe.
In order to determine the experience level, you need to go beyond how it "looks". Just because someone uses...
for($i = 0; $i < 10; $i++)
... in perl doesn't mean they are inexperienced. They may be doing this since they are old C programmers new to perl, or so that other C programmers that work with them could pick up the code easily.
The real way is to determine experience is to answer the question: How many actual bugs does this code currently (or initially) have? Examining the code sometimes turns these up, but testing and QA bean counting are probably better for this.