First off, let me do a little bragging.
[b]I just bought a PreBan Colt Sporter Lightweight Ser # SL0135XX w/small pushpin already drilled for the plunger, w/mag fence, grey upper/lower, flash suppressor, in absolutely pristine condition (it seriously looks unfired) the bolt carrier rails have no wear and the trigger group as well as the COLT sear block looks brand new. Ready for this, for $850 which happened to include a brand new condition Center Ind. 30 round magazine.[/b]

Now, why was it so cheap? After paying for it I asked if it was one of them "PreBan Weapons".
No lying, they told me it was made after the first ban but before the second ban which outlawed bayonet lugs???????  That's why it allowed to have a flash suppressor.

Now to make things even more interesting, last year I bought another Colt Sporter Lightweight in about 90% condition with a large hole lower  for $750 and when I asked then I was told the exact same thing.

[b]What the hell are they talking about?[/b]

Or maybe I was robbed and don't know it yet[;)]
Please educate me.

hes FOS on the second ban first was the 89 import ban only applyed to imported guns yours being made in USA was excempt later in the 80s???? colt  lopped off bayonets so they could sell ar15s to California. someone correct me if messed up any of that. it was purely political on Colts part to sell ars with out the bayonet lug.

cyrax-777  I think your right on where they seem to be confused.
I called Colt this morning and confirmed it as being PreBan.

Now I just have to decide what I'm gonna do with this rifle. I want to accessorise it in M4 style but the excellent condition has me thinking I should just leave it alone.

I don't know if California had anything to do with it...  Here's what I've been told.

Before 1989, Colt AR-15's were like all other AR-15's.  However, when Bush began mulling his now-infamous "assault weapons" executive order, Colt got worried.  It bagan to much with the internals of its AR-15's to make it harder to convert to fully automatic.  It also lopped off the bayo lug.  Bush was placated and only banned foreign "assault weapons."

No bans; it was Colt's own doing.  Oh, and you can go ahead and stick on an upper with a bayo lug if you desire.

Mike