I am thinking of buying a 5906 but as I live in "The Peoples Rep. of Massachusetts" I would like to get an idea of the age of the mags that are with it. If anyone could help I'd greatly appreciate it! The SN is VNH7###. Thank you all!

I have never seen a VNH s/n on a 3rd gen pistol - suggest you recheck (if not fully legible check under grip). If its VHN probably 1997/1998.
As to a few VLN, VMM, VUV pistols - various models mostly date to 1997/1998 but there are exceptions and there are VJH & VJL that date to 2002-2003 - so there would seem to be no logical order to prefix assignment vs year.

Suggest you check SW at [email protected] - give them model and full s/n and they can answer to "Manufacture Date" which may be actual manufacture date or more likely date it was packaged and box label created - either of which may significantly predate Ship Date which you can get from Roy below if you are a member.