I use a high-temp glue gun for lining clips & it's held up great - even in the Florida heat.
As far as a cordless glue gun, my personal recommendation is don't get one. At least not the kind from Wal-Mart. It's a PITA, the cord constantly comes out & it ended up being a piece of junk. I bought a new high-temp glue gun at Wal-Mart 2 weeks ago (with a cord) and it's great. It's by Adtech (grey with a white cord) and it's SO much better than the junky cordless one.