the penzoil full syn tcw3 is either purple or blue depending on your "man's" view on colors.
so IMO there is at least one Tcw3 oil that can meet that description, i know this because I used penzoil for a good 2 years on both my yami and my seadoo. (then i learned that seadoo took different oils, and switched) and contrary to some posts that say tcw3 will eat up your motor in a matter of hours, it won't, i easily put 70+ hours on my doo before I realized i was running the wrong oil, but it did gum up my raves...
with that said, heck, i might even consider just riding the ski until most of that oil is gone, then drain & replace, so as not to waste the oil, but that's not advice, just an option, the owner has to make that decision for themselves. I'll never advise running the wrong oil, or what could possibly be the wrong oil.
it really boils down to the fact that if you buy a ski and don't know 100% for sure what was used, then its best to drain, & replace rather than take a chance, in most cases that means your throwing away about $20 worth of oil, no biggie, you'll be throwing away plenty more money every time you take the ski out on the weekend.
$20 worth of wasted oil is just a drop in the pwc expense budget, not even worth considering.