My old company Brigg's & Stratton filed chapter 11 and do I need to file a claim for my 401K and pension money?

Briggs and Stratton filed chapter 11 and now I have received Form 410 (proof of claim). Do I need to fill this out to make sure I get my pension money at 65? Pension is run by Brigg's. What about my left over 401K money. I have not work at Briggs since 2009 so 401K is a stand alone entity and the pension is in an annuity for $$$/month until I die. Do I still need to file?