I came across a preban Colt AR15 sporter with an Hbar, serial # 241xxx. The place of business has checked on it to make sure it's a preban. It has a muzzle brake that looks like a flash hider which hasn't been soldered or pinned. He told me he would let me have it for $1200. It is in good shape 90-95% finish.
Is this a good buy for a sporter?
Input please, as it's not going to be there long and I am considering putting it on layaway until I get my tax money back.

Thanks.

Here's the link to the Colt serial number list off the old site main page:

http://www.ar15.com/legal/serialNumberList.asp

Check to see if it has the lower receiver block and the odd size pins for the fire control group and/or take down pins.  For another $100 bucks or so you can get an Eagle Arms or Bush and everything will be standard.  I have a pre-B Colt and it's OK, just a pain in the arse because it won't except my other uppers and has to have the extra cost triggers.

Need more info. Is the receiver marked Colt AR-15 A2 Sporter II? What is the two letter code preceding the SN? Any accessories with it? How many and what type of mags?  

If it's a blue label without a receiver block it's an good price depending on where you are located.