There is a reason we call our RV the Blue Flame. We have a 2004 Freightliner Showhauler with flames on the fiberglass hood. After 15 years, the decals on our hood were crazing. Even though the RV was inside 50% of the time, the sun finally got to it. The rest of the RV's decals looked great. So that's one caution, decals don't last forever.
We had a hard time finding someone to finding someone to redo the flames. The first issue was the original decals were printed via an inkjet type printer to get a color gradient across the length of the flames. No one wanted to try recreating that. Second, I had someone tell me they didn't want to work with the curves of the hood.
We finally found a guy in Phoenix that was willing to tackle the job. The solution was to use vinyl used to detail cars. We matched the blue that was at the front of the cab doors. Cost was $850 dollars. It looks SO MUCH better now!
I wrote a whole blogpost on the process. You can find it at https://rv.cjsquare.com/2019/05/the-blue-flame-gets-a-nose-job/ Usually the blog is private, but I opened it up so you can see what we had to do to get our graphics replaced. Feel free to check it out.