Yes, you can allow your clients to choose a shipping speed at checkout!
You'll turn this setting on by going to Commerce > Pricing, then click on the individual price sheet.
On Lab Fulfilled Price Sheets
If you want your clients to pay the same amount in shipping that the lab charges your studio, make sure that you've toggled on the "Charge my customers the same shipping amount as the lab charges my studio." option. Then you can toggle on the additional "Allow client to select the shipping speed at checkout" option which will allow your clients to choose any shipping speed offered through our partnership with that particular lab.
(Please keep in mind that these shipping options do not include in-lab production time, nor do they include the time it takes your studio to approve the order for printing.)
*If you want to create your own shipping options on a Lab Fulfilled price sheet, simply toggle off the "Charge my customers the same shipping amount as the lab charges my studio." option and add your own shipping speed option(s). Read more about this here.
On Self-fulfilled Price Sheets
Clients will see all of the shipping options that you create and will be able to choose the type or speed of shipping that they desire at checkout. If you do not add a shipping option, the client will not be charged.