(52144-356-005) CAP,DUST SEAL

If these are doing there job correctly, they will not allow the incursion of dust and grit into your swing-arm bearing, so if you are unsure, especially if you are re-building this area of your Honda, then renewal would be a sensible option?
For all the parts you require for this area of your machine, take a look at the online catalogue or where applicable the online 'parts list' fiche. This service supports many of the classic Hondas this item is used on.

Note: this part is superseded by 52144356005.