Robert: Most generators have a distorted sine output, depends on rating, and design.
Some have quite high THD. Other have terrible transients and EMI. Normally the mfg will have complete specs.
Rule of thumb: Larger size and high cost - (10..50 kVA) are closer to sinewave, low THD and transients
Cheaper consumer generators eg from Costco, under a few KVA, worse in every respect!
What is your intended use, and what power levels, make and model of generator?
I have used battery operated portables like TEK 212, rather than line powered scopes like 465M.
But you can float the 465 with an isolation trsf.