Question about promo stamps...

I got a copy of Dio's Strange Highways with one of those gold promo stamps on it, and today I replaced it with an copy without it... is the promo copy worth holding onto as a collectors item?

No, probably not. It's just a common CD with a promo stamp. I think the only promo items that are typically worth something are promotional only singles and EPs that were never available to the general public, typically with non-LP tracks or remixes.

Album promos are generally only worth something if the songs are different, which sometimes they are. For instance, I have a System Of A Down promo of their first album which is essentially an early mix of the album. Three songs have pretty prominent differences (just effects, no intros, etc.), and "Spiders" is listed as "Slow." These kinds of promos are worth something.

Yours is not. It's just the retail version with a promo stamp.

I've gotten dozens of old promotional CDs in used CD stores over the years. I always chuckle at the legal lingo on'em, i.e. "This CD is the property of (name of record label) and must be returned on demand."

Do the labels ever demand their return? Cuz they can have mine when they pry them from my cold dead fingers!!

Labels have no legal right to demand them back anyway. It's just nonsense.