So the MC's cheat skill is appraisal... Why did he not try to use it on the eggs?
If they are really dragon eggs with a dragon pup in them, then he should have been able to use appraisal on them just like he can appraise humans because the dragon pups in the eggs would be alive.
Therefore if he would not be able to use his appraisal skill on the eggs he would know that there is no living being inside and as such that they are fakes.
And if those eggs do have some lizards in them instead of dragons his appraisal skill would tell him that as well.
After all there is no reason he can appraise humans but not other living beings.
Hence either he can appraise what living being it is or he knows that it is not a living being at all.