I completely agree. My first compact mac was originally my parent's first machine, a Mac SE. My second was a Plus I picked up at the local Goodwill. My third was an SE/30, frankensteined together with parts from eBay and craigslist.
Part of collecting and preserving these machines is to also preserve their story (I know it sounds cheesy, but it's true). Many sellers on ebay don't say much about their products.