"immigration services" is a broad term that includes many things, not just PR landings. this doesn't necessarily mean the office doesn't handle PR landings. as steaky suggested, the best way to confirm is to call the specific CBSA office.
I emailed CBSA website about this a while ago, and they said they are changing to allow immigration at every point of entry, so they took it off the website. If you wish to confirm this, just phone them.