"...previous owner fired it..." That proves nothing about anything. Except he didn't know what he was about. Only headspace gauges prove good headspace.
"...& Commonwealth weapons..." Absolutely not CF Cadets. No paint of any kind on the No. 4's or No. 7's I had on my MIU, long ago. Mind you, none of 'em were DP'd. No such thing as no weapons techs available either.
"...many were converted back to firing status..." None of those are considered safe to shoot either.