I don’t think there’s any specific rules per-say but best etiquette is a price with a photo or two for the item.
Typically try to stay with PayPal Goods & Services for both sides protection or local sale if possible. This is the members classified area:
https://www.camaro6.com/forums/forumdisplay.php?f=278
You could also try the regional subforum for any luck for a local sale