Oddly enough (or not) I would be to afraid to touch those decals which should be replaced with ones that do not have the Eagles flying backwards.
I think the last time I applied a deacl/sticker (Airfix model) was before New Zealand had colour television (1973)
Would they be a decal or some form of water transfer ?
How would they be removed and will hope the PO did not use some form of clear over them.
The tank is original paint so would not want to damage it, I am more at home drilling holes in crankshafts.