Removing vintage badging requires a little finesse'.
Most numerals, letters and badges fitted to 'real older models' had small diameter posts molded to their insides which. allowed the piece to be placed into pre-drilled holes where they belonged on sheet metal.
The post were part of the 'badge'. Made when the part was stamped-out, poured or injection molded.
When the posts were inserted into their placement holes; one of many forms of speed-clips were pressed on to them securing the item in place, ... firmly.
If your badging is secured to the Deck Lid ( anywhere ) with a speed-clip type device; DON'T mess around trying to pry them loose. More often than not ---> on vintage cars; the post will break-off,... possibly ruining the badge.
Remove those speed fasteners like you are a Bomb Disposal Technician called upon to save the world!
DREMEL™ Tool and Cut-Off Discs (wafers).
The new model Cordless is ideal. Remove the speed clips by cutting them away from around the post. Cut the fastener away from the outside diameter of the mounting post.
Cut as close to the pillar without damaging the post.
Yes, ... you are destroying the rusted-on speed clip in order to save the badge.
No ... big ... deal.
You'll be able to buy a whole box of 50 - to - 100 of brand new ones for under 10-bucks!