which mechanical fuel pump 7.4

guys, I'm posting here because I don't see a Mercruiser MIE section and just want to get it right. I have a 1990 Mercruiser mie 7.4 which is essentially same thing as Crusader with a few bolt on differences I believe......looking for verification of which mechanical fuel pump to buy. A parts catalog I found shows it to be a Carter M60601. I think the one that's on there now is an after market Sierra. I'm curious because the Sierra pump for this engine is popping up at around $160 everywhere, yet Rock Auto has the oem Carter M60601 for $40 bucks. They look identical but the Sierra seems to have some sort of black exterior coating, I don't think its paint. What's up? And why would I not buy the oem Carter?

It should work...the inlet/outlet clocking may be different so that may have to be adjusted...

I checked my overhaul list and we used AIRTEX 60502's on our big blocks last time they were changed.

Big thing is to make sure the Pump OEM rates the pump for Marine Service...