Tinysine GSM shield impossible to run interrupts with Uno??

Hi guys

would I be correct in saying this GSM shield is impossible to run interrupts on because pis 2 and 3 are being used for the serial communication (rx & tx).

There is an option to switch over to to hard serial (HW) but apparently that is only possible with the Mega.

Any advise appreciated. Thanks

http://www.tinyosshop.com/datasheet/GSM%20Shield%20Datasheet.pdf