Well, it's complicated. In theory anybody on Star Trek could've pulled up some old Federation archives of Stargate episodes and watched them. But anyone on Stargate almost certainly had
watched Star Trek growing up. This creates a temporal paradox because a Stargate character could've referenced a Star Trek episode where a Star Fleet officer mentioned how that particular Stargate episode ended, allowing the Stargate characters to alter their fate. But if they did that it would've changed the Star Trek episode, etc.
Mindbending isn't it?