PL Grading

That's odd because the title of the sets after 2010 are called P-L sets. I'm assuming that's Proof Like.

No straight from the mint it says that.

No it doesn't.The mint has never used the term PL, the sets have always been called "uncirculated" or "brilliant uncirculated".

Up to and including 1967 PL coins in Canadian circulated sets indeed were specially minted, keeping in mind this was prior to the minting of RCM issued Proof sets which I believe began in the year 1981.

More information regarding those older PL sets can be found here:
http://www.edmontoncoinclub.com/cameo.htm

Then between 1968 and 2010 Uncirculated sets contained coins with a Brillaint finish (BU), aka all shiny, that is also commonly referred to as PL even though it is vastly different to the very attractive frosted/cameo effects of PL in earlier years. This BU finish is sometimes also referred to as MS-Uncirculated. (The only exception was 1996 and 1997 when Uncirculated Set coins were issued in Specimen finish.) The same PL reference for the two distinct types of minted coin is somewhat confusing.

Beginning in 2011 coins in Uncirculated Sets, as DBM mentioned, are the exactly the same (new) coinage that is otherwise issued to be circulated.

Edit to add: After 1967, the standard grade issued in Uncirculated Sets was PL-65. Considering they are low cost, mass produced sets the quality is not exceptional.