Old lens - how do I tell?

I've had this Sigma lens for I think 10 years and I'm trying to figure out how much I should sell it for, but I'm not sure where to find the specs for it? Does anyone have any idea of how to go about figuring this out? I've checked the Sigma site and can't find any specs for it (not even in the discontinued lens section).

Attached is a pic.

Sigma AF Aspherical
24-70mm
1:3.5-5.6

There's a stamped # on it? 2005747

HOSTED PHOTO
please log in to view hosted photos in full size.

Lens was introduced in 1994...... http://www.sigmauser.e​u …es/museum/19942​870MZA.htm

That being said, you would probably need to assure potential buyers that it will be compatible with today's DSLR's as I'm guessing Sigma wouldn't re-chip a lens that old...but who knows.

Hope this helps.

Thanks a bunch.

I have put this on my XSi and it takes one or two pics then freezes the camera. So I can guarantee it won't work with a DSLR.

I guess I could put it up on e-bay for SLR people.