What methylation values are usually supplied within ncbi geo 450k series matrices?

I am going to automatically download a lot of GSE (~80) matrices and to use them in my analysis. Before this I want to double check here if I understand correctly what data is within those matrices.

I know that they contain sample, contact information, etc. But what about methylation data? Are those values already **normalised, batch corrected**? Or does this vary between each study?
The methylation values are included in the GSE, yes. The values vary between studies. In general, they will be normalized, but the normalization methods will vary from GSE to GSE.