Exactly - I thought the lion was MGM. Universal's the planet, still, right? (And I miss the Tristar pegasus...)
Aww, yeah, the pagasus - I miss that clip of him jumping over the big logo.
Anyway, as has been mentioned symbols - even seemingly-universal symbols - may have different meanings in a specific work. For instance, lions. Sometimes they represent nobility or bravery. But they might also represent savagery or the brutal power of primal instincts - they're a top predator in their ecosystem, after all. And recent research indicates that lions steal kills from hyenas more often than hyenas steal from lions; maybe lions could represent deceit in a story. To a character from Africa, lions might represent her homeland or her lost childhood. You have to give the reader some context clues so they know what you're representing with a given symbol, especially the first time or two you bring it up.
My novel is set in ancient Egypt, so I had to provide some context for all the religious symbolism I use. In Egyptian mythology, the goddess Sekhmet is a lioness who is sent to punish mankind for conspiring against Ra. But she kills so many there will be none left to worship the gods, so Ra dyes beer red with ochre and pours it in a big lake, and she laps it all up, thinking it blood, then falls into a drunken stupour. I play on this myth a lot in my novel, referencing excessive beer consumption as pacifier/loss of control, but also inverting it as an incitement to wrath, red dye being used to play tricks on people, and lionesses being associated with vengeance. Because thats a lot of complexity to get across, I have someone quote this myth right in chapter 1, fittingly as he is about to get drunk
So yeah, I think if you need to set out the context, then do so, but try to make the explanation part of the story/scene, rather than an obvious piece of exposition.