Head Spacing

I have reloaded over 3500 rounds of 7.62 LC with the same LEE sizing die, the the headspace for these rounds and everything is fine. I know this may sound stupid but how about all the FC and RP cases I resized with the same LEE sizing die? Should I recheck headspace, "which I am sure I would anyway", or since the same die was used, would the cases all be the same and headspace would still be OK? I have read somewhere that the military cases spring back a bit, so the head spacing may need to be checked fore the civilian brass even though the same die was used.