I had a couple of P6's when they first started dumping them on the market. One was an early date and well worn and apparently shot a good bit by the looks of the smiley on the barrel, the other, a later date, and near new, and looked to have been shot very little.
Both needed the mainspring replaced with a 225 mainspring, to bring the trigger more into line with the commercial SIG's I had. The trigger as they come is fairly heavy.
There is an approximate cutoff date for a barrel change that helps with feeding HP's. Dont remember when that was, but Im sure a search will show it. There were some pics floating around showing the differences in the ramps too. Both of mine fed anything I put in them. One had the early version, the other, the later.
I had a bunch of mags and I made out when I got rid of my guns. I sold the mags separately on EBay, and made a good buck doing so too. By then, they had pretty much dried up, and prices were at or above what a commercial P225 mag was going for.
Both of my guns were accurate and reliable, like all my other P series SIG's.
If you like it and have the change, go for it, I doubt youll be disappointed. They are an "old school" SIG, and great guns.