yes that is def your castor buses, pretty hard to do your self so best to take it to a work shop to do it,
mine were like that but i then decided to get them replaced with a polyurethane bush kit that superpro make, for a few $ more i went for adjustable castor bushes, which gives you adjustable castor, to help tune in more wheel alignment specs to help the car drive straight,
when your stock bush completely drains out, you might notice that the car will pull to one side, but its not something that will cause immediate dramas
workshops shouldnt charge a hell of a lot in terms of hours, its only a few bolts, then they have to press the old bush out and put the new one in (extremly hard to do your self) then it will need a wheel alignment
the part numbers for an r33 for the superpro bush kit
-1202k - direct standard spec replacment
-1202AK - adjustable caster(worth it )