I need some help with a price check on a used Colt M4 upper that I found.  It's a complete 14.5 incher with all the Colt markings, white RAS numbers and includes the removable Colt carry handle.  The seller says it probably only has around 100 rds through it and he is asking $750.00 FIRM.  

I got to looking at it and the exterior finish looks pretty good except for a small chip down to the metal on the sharp edge of the brass deflector.  The barrel and bore look good, bright and shiny (marked 09/02), but the bolt carrier, bolt and inside of the recriver look to me like they've seen more than 100 rds.  By this I mean that the long raised edges on the BC near the carrier key and the sides of the key itself are worn shiny along with areas inside the receiver where the charging handle would move back and forth.  The bolt lugs appear square with not much wear but the bolt face does seem to have some contact wear.  Also, the relief area inside the reciever (half circle looking area) where the bolt cam pin moves around has a small dent and flat spot worn down to bare metal as if the cam pin has come into contact with it.  I seem to remember my Bushy upper had this same mark, so maybe this is normal as the cam pin moves back and forth in that area?  The cam pin itself appears fairly worn but the cut-out in the BC where it moves around does not.  Lastly, the front hole where the lower receiver detent pin goes through is very tight about half way through when I try and push the pin in to mount the upper on my Colt lower.  The hole does not look out of round and there are no deformities that I can see to the front receiver lug.

Mechanically it all seems to be fine but without actually taking it out and shooting it I don't know what else to look for.  I don't mind paying this price if it is fair, especially since a new Colt 14.5 costs between $900-$1100 depending on where you look,  but I don't want to get ripped off either.  I'm hoping that some of the more Colt savvy of you out there can help me out with this.  I'm trying to put together an all Colt rifle and this would rap it up.  If this is a fair price I'll be happy, but is there anything else I should be looking for or concerned with?  Thanks in advance...

Anyone.....?

750 seems a bit much to me on a used upper.  An new LMT would cost hundreds less.  I'm not sure about colt valuation though, someone should be along shortly that does though...

You can piece together a new Colt upper for $650.

The only time I would pay $900 is if the upper was new, matching, and out of production markings for a clone.

$750 is too much.