>>9142689Nah, it isn't unless you are a boomer with extremely unsteady hands or something. Just sand it down with a sanding stick, it doesn't need to be perfectly flat. I've done plenty where I've half assed the sanding and they go on just fine. The only time it will be an issue is if they're super pronounced, but afaik if they have some super pronounced part ie the cone/sun shield thing the Mig 21 radar has, Eduard will build the photo etch around it.
source: Someone who has never built a plane kit without using Eduard cockpit sets (or obscure resin ones if theres no eduard one) in his life.