Yes, the spacer is a good thing to put in.. learned the hard way man .. and make sure you put the grooved side towards the bearings also, ive seen a few people who put the seals in backwards.. Just incase you didnt know, you need to get some bearing grease also.. i find it easier to use a socket the size of outer ring on the bearing to hit them in, goes in strait that way, i cant think of the size at the moment but you get the picture.. Didnt you ask us about the carrier bearings a while ago? Goodluck..
Eric