Correct Water Pump for Early 273 w/ AC

I ordered the Gates 42553 water pump listed on Rock Auto for my 65 Dart 273 with AC. But when I compared it to the old pump I noticed a problem.

It has an extra 1/2 NPT inlet on the top left.
View attachment New Pump.jpg

This inlet creates a bulge in the water pump casting between the two bolt holes where the AC compressor bracket is supposed to mount. Here is a photo of my old water pump with the AC compressor and other brackets attached.
View attachment Old Pum.jpg

Do I have the wrong water pump, or do I have the wrong AC compressor bracket? I've combed through photos of other early A's with AC and they seem to have different alternator brackets than I do, although none of the pictures really shows the AC compressor brackets.
View attachment Brackets.jpg

There are four other water pumps listed on Rock Auto, all with pictures, and none of them has this extra inlet. Only the one I purchased, which is the only one called out for cars with AC, has this extra inlet, although the photo provided does not show the top of this pump with the extra inlet. I can't imagine what this extra inlet would be used for, or how it would be necessary for Air Conditioning.

I have read that 1965 cars with Air Conditioning got a different water pump with extra blades on the impeller. But I don't know how many blades. The Gates pump has 8 blades.