Do black holes exlode at the end of it's life

If so, it would emit a lot of gamma rays. Do scientists think that possibly that the gamma ray bursts are "small" old black holes "exploding"?

Yes; due to a phenomenon known as hawking radiation, a black hole will gradually emit all of its mass away. A black hole will eventually shed off so much weight from hawking radiation that eventually it won't have enough gravity to hold its contents together, and when this happens, it will dissapear in a brief burst of radiation.

No

No, gamma ray bursts are not black holes "exploding". I believe they are thought to be from the formation of a black hole, or material being sucked into one.

Hawking radiation is only significant for microscopic black holes.. For a "normal" one, I think it would take billions of times the lifetime of the universe to decay by Hawking radiation, even if no extra matter or radiation fell into it to counteract the Hawking losses.