I have read the pre ban FAQs a couple times and I still have some questions.

1) If you find a pre ban reciever, you have no way of telling if it is legal since you can't prove it was a complete rifle before 1994, right?

2) How do you know if a pre ban gun was assembled out of pre ban parts that weren't an actual rifle prior to 1994 making them illegal?

3) Did you have to register your lowers back in the 70s & 80s?  If you didn't, how the heck would anybody know if it was ever a complete rifle before 1994?

4) What good are serial numbers if they don't give you the whole story?

This all seems very confusing.

"This all seems very confusing"

Welcome to the world of gun ownership!

Unless  you use it to commit a crime, nobody will say anything.  I'd say maybe 2 out of 100 cops or ATF have a clue.  Out of those 2, how many would really care....ZERO.  Just buy or build what you want.

Some manufacturers, like Colt, only sold complete weapons pre-ban.  The serial number range is know for pre-ban Colt ARs.

Otherwise, with other manufacturere, it's a crap shoot.  

Let me try and help out.  I spent an evening reading a FAQ put out by the American Terrorist Federation (ATF) that is available as a pdf doc. This is my understanding.

1)No,  there are lists of the verified pre-ban serial numbers.  One of the best is in scott duff's ar-15 owners guide.

2)ask the mfg., who may know.  Many mfg. kept lists and can tell you if it went out as a complete rifle or just as a lower.  If it went out as a lower they can't tell you if it is pre-ban or not b/c they don't know when it was made into one of those evil assualt rifles that we have to save the children from.

3&4)Depends on what you mean register.  All guns have had to have serial numbers for a long time.
The serial number has nothing to do with it being pre/post ban.  The key date is the date that it was made into an evil assualt rifle.  A lower created and given a serial number one year before the 94 cut off date sits in your house until after the ban date and then you decide to make a rifle.  It's a post ban and so you lose.  You see, it is not an assualt rifle until it has the extra evil child killing features like flash hider and bayonet lug.


Other:

I've never seen an ATF definition of what had to be with the lower to constitute a rifle.  If anyone does please tell.

[url]http://www.biggerhammer.net/ar15/ar15serial.html[/url]

This is the SN list for Colts.

MOD

How the heck would anyone know when you made it into an assault rifle?  They wouldn't.

Realistically you probably can't tell, I don't know.  I don't know who the burden of proof falls on to prove when it was made but I'm sure if the American Terrorist Fed. wanted to they could make you unhappy in the mean time.