firebox approved for gas-logs?

After reading some of the old posts of a.h.r in Google groups on vent-free gas logs, I saw those who actually had them were well pleased with them. Even my co-worker likes his gas log.
My question is how can you tell if the firebox is approved for vent-free gas logs? My firebox is metal and has three fake brick walls. The brand is Superior, model SFGR-38.
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If it is approved for vent free, it will say so in a label attached to the firebox if manufacturer in the last 10 years or so (1995, I think). Or contact Superior at:
Superior Fireplace by Lennox Hearth Products 1110 West Taft Avenue PO Box 14233 Orange, CA 92865-4150
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Phone: (714)921-6100 Fax: (714)521-5223 Email: snipped-for-privacy@lennoxhp.com Website: www.lennoxhearthproducts.com

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