What would be the going rate for these? they're marked- colt ar-15.
Thanks for any replies.

Pass on 'em if they don't have aluminum followers.  USGI mags (with the aluminum followers) like these should be under $20 in like new condition, certainly under $25.

Colt never made magazines, these are likely Universal Industries and will be so marked on the mag body.

-- Chuck

if that is all the markings on the floor plate.., they are trash !! made in China or some other commie hole in the Earth......

Sorry, I should have been more detailed
they are marked as follows:
(picture of pony) COLT AR-15
CAL 5.56mm
COLT'S PT. F.A. MFG. CO. INC.
HARTFORD. CONN. U.S.A

the body has the UI symbol on it and the follower is aluminum.
So these are the one's you are talking about that should be less than $20 correct Chuck?
Thanks again.
Edited to add:
also if I sold these should I refinish them with some perma-slik I have? Or is there any reason I should leave the original finish on?
Thanks.

These are premium quality USGI M16 magazines and should be in the $20 - $25 range (unless you're looking for collector condition).  

Georgia Precision sells them as do other folks.  GA-P sells them in refinished condition using PermaSilk-G and they're hard to tell from new.  They sent me a reconditioned mag I received 24 Oct 01 and she's always in my range bag, so gets shot every time I go to the range.  Finish holds up well.

-- Chuck

that is what you should have typed in the first note..., you have some good mags !! but if not in excellent condition i'd put them at $15-$20 each, i try to buy large quanity of mags, that way they average out pretty good, my last buy (21) had 5 that appeared nearly new, no ding on the raised portion of metal follower, & two were well used but still very functional......