Mystery holes

[Scott70RR440]

When cleaning my floor under rear seat i found 2 roughly 5/16 holes that were covered in blue silicone. Im highly doubtful these are factory but i thought i would ask.
Thx

 

[eldubb440]

someone used a self tapper from underneath for an exhaust hanger?

 

[tonysrt]

Probably not factory, is there anything under the car near those holes? Maybe P.O. used them to support something under the car.