Egyptian Ak 47 Serial Numbers

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Egyptian Ak 47 Serial Numbers Rating: 5,0/5 6421 reviews
I’m trying to determine if this Norinco MAK-90 is pre or post ban.
I’ve had this rifle for longer than I can remember and recently thought about selling it, so I brought it out and figured I’d do a little research on it before I did. I always thought this was a post-ban rifle because of the thumb-hole stock, but I read that the year of manufacture was actually stamped in front of the serial number and since the entire serial number reads 91134546, I’m now thinking that this rifle was actually manufactured in 91’ (1991), if that’s the case, then that would mean that the rifle is actually a pre-ban correct?
Any input would be greatly appreciated as I do not want to misrepresent the rifle when I sell it and get myself or anyone else in any possible trouble.
This is what I have so far;
NORINCO = Export Company
MAK-90 SPORTER = The letters/numbers MAK-90 stand for Modified AK-1990
CAL 7.62x39mm = Caliber
The serial number is 91134546 = Made in 91’??????????????
C.J.A SFLD M1 = C.J.A. (China Jing An), Springfield, Michigan
The letter 'U' in front of the bolt = ????????????????