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Warm them up with a heat gun and work some fishing line behind them to get them off the tank. You'll be left with residue on the tank, which can be removed with a few doses of WD40. Good luck.
Just my thoughts ... A 1992 model? Maybe they didn't use clear coat back then. That's 16 years ago. Look real close at the broken edges. If it appears the decals are on top of the paint then you may be able to remove them using the methods listed above. But if it looks like there may be a clear coat on top of the decals I would wait.