Chainsaws

I have an older 55 Rancher Numbers on the ID tag are as follows: 967 05 29-00
00 3200741
It still runs great and operates well I just need to do some upkeep maintenance.(The muffler melted the chain brake handle, etc.)
How do I properly locate replacement parts for this saw? Everywhere I look the Models are so confusing.

Thanks,

Jeff Brown