I have an A1 complete upper with B/BC that I am considering selling.  However, I am not sure what price I should ask.  Of course, I would like to get the most I can for it, but I don't want to ask for too much and not get any responses.

Although the upper came from a preban colt lower, I am not certain of the manufacturer as it does not seem to have any markings.  How would I verify the manufacturer?  May there be markings under the handguard?  What about the bolt and carrier?

Here is a pic of the upper.  As you can see, it has a teardrop forward assist with no deflector.  Full birdcage FS w/no bayo lug.  The upper also has a triangular handguard cap.  Thanks in advance for any help or insight.