I'm not sure you can even make that change. I think the one you have is thinner than the bearing with the alum. cage. Which means the drive wouldn't go all the way on. The OD may be different also.
My 69 160 sn2497444 had the plastic one. I swapped it out last year for the aluminum one. Mine isn't set up to grease the bearing from the outside so I put in the aluminum one with the slots facing aft so I could twist the bearing out each year to grease it. I know you're not supposed to do it this way, but it works for me.