Yeah, it should be, since IVs and innate values are kept unless you KO them and beat the E4 (in which case, your odds of getting another shiny are pretty damn slim).
This is, of course, assuming that this happened in a DS cartridge, but I think it's the same case with the GBC games, too (unless you do kill them, in which case they won't return).
I didn't encounter my first shiny until Platinum, excluding the red gyarados in Gold. Of course, I didn't know what shinies were before Platinum either. Anyway, my first one was a Golduck that I encountered while surfing. Since then, I've gotten about six more shinies, mostly on Platinum, with one or two on HeartGold. Only about half of them were from chaining.
I found both my first two shinies non-Radar, but they're... sort of the only ones, and a damn critical killed one of them. Both on games released long before Platinum.
My first shiny Pokemon was a shiny Wingull. I was playing my Sapphire version and I ran into a shiny Wingull Level 18. Then a month later or so my game got deleted. then I played my Sapphire version again and restored a root fossil and got a Level 20 shiny Lileep. Then the game got deleted again. -_-
I also have a Platinum verison for Chirstmas last year and the version has all Pokemon Shiny and Level 100. :D
If that was while you had the DS games (or, those were at least out at the time), you should've just Palparked them while you had the chance.
Never got a shiny out of what I received or revived, sadly.
Also, use the edit button next time.
The uncatchable poocyena in Ruby was my first gen 3 shiny! Argh!
Sandslash in Crystal. It actually is my first shiny ever since I didn't catch the Red Gyarados. Darn Togetic and its Metronome which became Explosion...
Though this was at a time I didn't know what shinies were so I thought it was a glitch in the game that Sandslash was green all of a sudden. XD I remember trying to breed it to get a green Sandshrew as well.
I think it was a Cyndaquil. I was trying to get a female Cyndaquil, so I kept resetting the game. It was a looong time ago, though. I think I lost it when Gold's battery ran dry just recently, UGH. DX
Current White Team: