[inspectorudy]

No they are not the same part. The hex bolt with the numbers on it is just visible behind the port outlet that you have circled. There is also another one by the other port with the underlined C. To me they look like they may have been alternative port openings for larger size outlets at each port location and that these are just hole plugs. If you go up to my three picture set and look at the one in the middle that is the large numbered hex bolt and the high pressure port next to it on the bottom of the picture. And the low pressure port is visible too, on the top side of the picture, with the smaller hex head bolt with the underlined C, next to it.