I've got quite a bit of cedar fencing around my house, none of it came treated. Given it's natural resistance to rot, etc. I can't imagine that the stuff you've found would be. If it's been painted or stained, all bets are off.
Same with cedar tubafors...redwood ones too for that matter...
John E
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JohnE
"and all the lousy little poets
comin round
tryin' to sound like Charlie Manson"
The Future/Leonard Cohen