PBGC isnt exactly in great health either. I wouldnt trust anything with GE and take the bird in the hand and run
The often-reported status of PBGC's funding generally refers to multiple-employer plans. In the case of a single-employer plan, its funds are for its own purpose first. With A partial pension, I wouldn't worry much, even if they took over the plan.
(I am speaking as someone who is in this situation)
The PBGC does have coverage caps, but they are multiples of $970 per month.
There is something to be said about a bird in the hand. GM went through a similar process, and in the end moved the pensions to an outside insurance company. (Metlife?) So, they literally became annuities. But, they also no longer depended on GM's health. But it does seem like the offer is low; if anything, the low interest rate environment should inflate the lump sum amount, since it's the payout that is fixed.
One other point, if you go forward with it: you should be able to roll it over into a tIRA.