I’ve been able to salvage decals by clear coating them first , tamiya clear can be a bit “hot” tho so I’d do a light mist coat first then a heavier coat , test a decal you can spare in case it reacts poorly with them, also I’d use a gloss or semi gloss vs pure flat. Lastly, worse case if it doesn’t work one of the decal places , like sts, can certainly reprocuce them from a copy or pic and their prices are reasonable