Ordering a JLU, need advise

I will be placing an order this week for my JLU.

Apparently the door sills have an option to get stainless steel sill guards for 195.00 or plastic for 125.00.
Are these sills guards bolted into the Jeep or glued on?
Is there after market sills that are better and for less money?
Should I just get one of these and not worry about it?

Any advise is helpful.

Thanks,
Jeepers Creepers