I have a 68 Dart GTS 340. I'm rebuilding the carburetor and my Carter AVS 4425S isn't exactly like those I see on the Internet. All the ones I see on the Internet have two idle adjustment screws but mine only has one as you can see in the images. The holes where it appears there should be two are plugged. Any idea why and is it unusual? Also, any idea what the H7 means? Is that the month and year of manufacture?