I did a suspension install last spring/summer with Illuminas/S-Techs. The only thing I replaced were all four dust boots. Recently, I have heard a squeaking coming from either just the rear right or both. It is very intermittent and doesn't seem to be getting worse or anything. It happens on decently smooth roads as well as bumpier ones. Any ideas? Is it most likely the mounts or what?

(Suspension has been flawless up until now.)

Thanks