I am getting ready to build a M4A3 clone.  I am going to buy a Pre Ban Colt lower, I just don't know which one looks the most like a military piece?
 I see a lot of lowers marked blue label, green label, slabside, raised fence, large pins, small pins, sear block, no sear block.  I know I definitely want a raised fence, I just don't know about the other features.
 Can one of you AR Gurus shed some light on this for me?  Thanks

You know that's a good question. I was thinking of a similar project but would like as close to a "mil-spec" lower as I could get. And that isn't a Colt as far as I know. Don't know much about quality pre-ban lowers. I think I'll wait for the Assault weapon bill to fall off the planet and then do one ! Would be cheaper if the law changes. If it doesn't, I'll suck it up & do an M4.

Well, to be cosmetically correct externally you need a raised fence and small pivot pin. The larger fire control pins probably wouldn't be very noticeable. The sear block is not visible from the outside. The problem with being too picky is that a pre-ban Colt with small pivot pin, small fire control pins, raised fence, and no sear block would be rare, if not non-existent. A blue label will probably be your best choice.