Be sure to read the batting instructions.
Some battings - the package says Do Not Wash before quilting. Believe what it says.
Once upon a time I thought whatever it was was washable batting. It arrived in/at my house unpackaged, and I just - assumed - that it would be washable. I ended up with the biggest mass of kleenex like mess in my washing machine. Took a loooong time to get all that removed from my washer.
So - I would say that - "when in doubt about what you have" - either wash a small sample and see what happens or use it unwashed.