That depends on who is selling them. There are several reputable companies out there.
One of the things that you may use as a yard stick is how big is the dealer's presence at the show? Is it a small dealer with just a handful of parts or a good selection? In other words, do they look like they know what they're doing?
You can ask around the show about their reputation.
A few of the companies that offer parts and kits are:
Castle Arms, Inc [url]http://www.castle-arms.com/[/url]
Bushmaster [url]http://www.bushmaster.com/[/url]
Olympic Arms [url]http://www.olyarms.com/usa.html[/url]
Rock River Arms [url]http://www.rockriverarms.com/[/url]
Model 1 Sales [url]http://www.model1sales.com/[/url]
M & A Parts [url]http://www.m-aparts.com/[/url]
J&T Distributing [url]http://www.jtdistributing.com/[/url]
Fulton Armory [url]http://www.fulton-armory.com/[/url]
Hope this helps...
[sniper]
[b]The Sniper