Radios-uk Customer Service

The short answer to this question is NO.

PMR446 radios are made for use in Europe and Scandinavia. In the USA a similar radio is used (FRS)
It is not legal to use PMR446 radios in the USA without a licence.
It is not legal to use USA radios in the UK either.

The 446MHz frequency is a licensed frequency in the USA
If you are going the the USA for a stay you will need to purchase suitable FRS radios when you are there.