As has been said above, it's good for life as long as they don't change any retirements. In the past they have grandfathered previous approved courses to my understanding.
Couple points to consider:
You don't have to pay the full renewal fee, it's reduced based on how long till your PAL expires. 5 years to renew, cheap. 1 year, more expensive. Call the RCMP and they'll tell you how much will be required when you apply.
There shouldn't be an issue about loosing your proof. It's sent to the RCMP and they'll have it on your file, but it is a risk.
I'm in the may as well send it in group.