Is the surface of glass a fine layer of silanol?
Yes, it is correct that the surface of glass has silanol ($\ce{Si-O-H}$) at the surface. This is because water will react at the surface to relieve bond strain of a $\ce{Si-O-Si}$ bond to form $\ce{Si-O-H H-O-Si}$ pairs. additionally there is sodium siloxide at the surface ($\ce{Si-O-Na}$) which will release sodium hydroxide on contact with water $(\ce{Si-O-Na + H2O -&gt; Si-O-H + NaOH (aq)})$ and is major reason why normal glass cannot be used for biomedical implants.

Additionally these surface silanols can react with chlorosilanes to produce hydrophobic surfaces $$\ce{Si-O-H + Cl-SiR3 -&gt; Si-O-SiR3 + HCl}$$
where the R is a non-polar organic pendant group that is hydrophobic. This coating causes water to bead off of treated glass that would priory be wetting.