Ok so... where to start... I ordered a few things from Del-ton with my tax return this year, namely a AR15 BCG, charging handle, and 20" pre-ban barrel kit. The package took about two weeks (from what I've read, is pretty standard Del-Ton) and it arrived today. Everything is in good order and all of the below discrepancies are my fault mainly due to my lack understanding of the subject (being fairly new to the AR building thing). So here are my problems: 1. As it was "Pre-Ban" I thought that meant that the A2 front sight base would include a sling mount and bayonet lug (pre-ban barrel kit pic on DT's site showed a bayo lug on the FSB). The FSB that came with my package has the sling mount, but not a bayo lug. Am I confused on the whole pre-ban/post-ban jargon? 2. The kit came with taper pins, but neither the FSB nor the barrel are drilled for them. Not sure if that is my goof or DT's, but I feel that should have been mentioned in the site's description of the contents of the kit. Is there anyone who knows a gunsmith that can drill a barrel/FSB to accommodate the included taper pins? Tried Curt's (talked to Curt directly) and he said they only have the ability to drill and screw the FSB into the barrel. 3. And speaking of front sight bases, the AR build I am working on has the flat top upper receiver, with the removable carry handle rear sights (I'm wanting the rifle to be set up just like the M16A4 I was issued at basic training, too bad it'll be sans three shot burst) and I'm confused about the "F" marked FSB. Here is a copied and pasted description of the difference between the standard A2 FSB and the "F" marked one: "NOTE: F-Marked Front Sight Base is not compatible with an A2 Upper due to height compatibility, therefore if you choose an A2 Upper and want a standard front sight base you need to choose the Standard A2 Front Sight Base." So does that mean that a standard A2 FSB won't work with the flat top reciever/carry handle sight assembly? Would that mean I would have to find an F marked FSB with bayo lug to keep my rifle as close to mil-spec as possible and to be compatible with the flat top/removable carry handle combo? Any help/advice would be GREATLY appreciated. Thanks guys!