Maybe not glued in but it is pressed in! This was not done at the Mint unless they had a special program/event for inserting a Lincoln Cent in a Copper Ring to sell or give to folks but I do not know of any. The metal in the coin's planchet are different from the ring as is evidenced by the different coloration (i.e. toning/patina). While the coin's planchet comprises a content of .950 Copper and .050 Tin and Zinc, I believe that the ring that the coin sits in, was produced with more pure Copper. Sorry, but this was done Post Mint and is not an Error of any kind!
Thanks for noting this as I forgot to mention that in my previous post! The planchet would not fit into the Collar and probably the Striking Chamber as well.