Guardian mainspring housing..
 

I love my guardian but would love it more if the mainspring housing was checkered. I have been looking at ed brown housings for the job since im pretty sure dan wesson uses at least some of their parts. Does any one know if it would be a drop in part or if I would have to have a gunsmith make the part fit correctly. Also are there any other parts companies you guys would recommend?

Any mainspring housing should be a drop in fit but with a 1911 you never know!!:)

No such thing as a 'Drop-in' part.