Recently received a very good condition early-2nd Gen G17 that has the non-upgraded internals and the 90-degree ejection port. I've determined from my internet snooping that it is a candidate for the 6-part upgrade (the "firing pin upgrade"). The question I have is, why does it need this upgrade and what could/would happen if I didn't get the upgrade? Apparently (if what I've read is true) an LEO had an AD (and his armorer had an AD and a short burst of fully-automatic fire) which prompted Glock to have a recall/upgrade for the 6-part upgrade. Should I go ahead and have the upgrade done or is the original design OK?