Daed... its done all the time here in CT, where we also have similar "evil gun" postban laws. By all means, the easiest way is to take it to your local gunsmith (full service of course).
Bayo Lug: He'll take it apart, pull off the front sight / gas block and either grind the lug off, or if you want him to, will put on a single, bi or quad gas block without the A2 front sight for you. So much for the bayonet lug. (btw... I'm not a big fan of the A2 front sight anyway) Can it be done by leaving it on the barrel? I'm sure it can, but you better have a good solid vice to hold it. Much cleaner to remove and replace. I would be leery of having a hand held grinder that close to my barrel. Just me tho.... lol....
Flash Hider: If it is just screwed on, it should just screw off (if you live in a perfect world). If it's been pinned and "welded" the process is a bit more involved. In some cases, you have to cut away the flash hider, and may, depending on your cutting / chisel / prying skills... have to rethread the barrel to allow for a comp to be installed. The "pin and weld" is usually not a "real weld" as we think, but rather a filling of the pin hole with high temp solder or even a spot weld. I'm sure people here have seen full welds as well as spot welds...
Recoating: With the barrel off the reciever, a full service smith should have easy access to parkerizing. He'll simply repark the barrel. No need to repark the upper receiver. Cost around here to repark is about $50 or so, especially if he's doing other work at the same time. If the finish is Melonite, Tennifer, or one of the other new coatings.... its another story. I'm assuming the Colts are parkerized. In any case.... on a Colt? I wouldn't settle for over the counter bluing. I'd have it done. You COULD send the upper to Colt to have the work done for you if you don't have a Smith you trust.... I would imagine the lead time would be long, but the work would be done right. Have no idea on their pricing. Give them a call.
Now... I MAY have a detail or two misrepresented here, but I've only seen it done once, and have friends who have described their experiences to me. Your experiences may vary.
hope this helps you to understand what's involved.
Da
