Funny you say that mate, my latest one (had one before when they first came out and it did have that issue) received last month from 6mm, I forgot and left the mag in the gun overnight and the firing pin thingy didn't break, also accidentally inserted the mag couple of times without racking the slide and it's still ok, maybe WE has sorted it but I do still rack the slide before inserting the mag just incase, that is if I remember : ( .
In regards to the mags the reason I asked as HK retailers are selling them as old version/m1935 ones and MKIII :
http://armypanda.com/products/WE-Browning-Hi%2dPower-MK3-Original-Magazine-.html
and was hoping anyone with first hand experience could clarify.