Look on the side of the receiver for the address. If it is Windham, Maine you are looking at one of the best production AR's made. If it is from one of the New York towns it is by Remington and early Remingtons had production problems.
I bought my Bushmaster (AR-15A4) in 1996 for almost $900 ON SALE. All prices on AR's have come down, even though costs have risen, that profit difference was made up somewhere!!!
I took my Bushmaster home the first day and put a very good scope on it (Leupold Veri-X III 6.5-20) and had several boxes of Winchester promotional Varmint 46 Gr HP ammo. After zeroing, I shot six consecutive 5 shot groups, ALL were 1/4" or less! I went back to the store and ask my salesman (while he was in the middle of a sale), WHAT SIZE GROUP AM I SUPPOSE TO GET ON THAT RIFLE YOU SOLD ME YESTERDAY? The customer dropped his pen and stopped short of signing his transfer form. The salesman hung his head and said, They typically get 1 inch groups. I said I'm getting Quarter Inch groups! The customer grabbed the pen and signed. The salesman looked at me with a smile and said, "I can probably fix that if you like."
Ivan