Hi, I'm trying to get my parts for my motor thorugh Iboats. I have a 1967 Sportfour 60HP Evinrude. I assume what they refer to as "gear case seals" would be the lower unit? I came up with part # 18-2689 for the lower unit seals, and #18-3005 on the impeller. I'm hoping I'm on the right track.