Signed Edition vs. Unsigned Edition

Hello,

My question has to deal with the Batman Grendel Platinum Ashcan from the Hero magazine in 1993. There were 3 cover variations. Red moon in every edition of Hero #2. A gold cover given to shops for every 25 copies ordered. Then the silver, or platinum cover that was limited to only 25 copies that were contest giveaways. All were supposed to be signed by the artist. This is a limited number run and quite rare.

I own a copy of this comic, however mine is unsigned.

Upon first consideration I figured my copy would be worth less money because it isn't signed. However the more I though about it since all of the platinum versions are supposed to be signed then this one is rarer than the others are.

Would that make mine worth more because it isn't signed? That seems so backward but it's logical too.

Perhaps I'm thinking about it all wrong, not sure. So I though I should ask the question here & see what everyone else thinks.

Thanks for any feedback,
LD