I'd call Brownells if the new site is hard to use. THeir techs are extremely knowledgeable and will have the part to you in no time.
I wanted 2 sets of HK styled diopter back up sights for my ARs. I couldn't find them on the site as I couldn't remember the name of the sight or the manufacturer. I called and said exactly what I said above, and the tech replied--"Oh, sure, you mean the 360 battle sight". I was 15 minutes away on Highway 63, swung in, paid 'em off, and walked out with 2 back up sights just like that. The sights were waiting for me at receptions, and the secretary called me by name when I walked in.
Great company, great service.